6th to 8th January 2018 Tirupati, Andhra Pradesh, India e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Table of Contents
Welcome notes: Director, IISER Tirupati ...... ii Director, IIT Tirupati ...... iii President, ISAMP ...... iv Conveners, ISAMP-TC7 ...... v
ISAMP: History, Objectives, Executive Committee ...... vi
Conferences organised by ISAMP ...... vii
Advisory Committee ...... viii
Scientific Advisory Committee ...... viii
Organising Committees ...... ix
Program Schedule ...... xi
List of Abstracts ...... xiii
Abstracts: Keynote Addresses ...... 2 Invited Speakers ...... 5 Contributed Speakers ...... 48 Posters ...... 60
About Tirupati, IISER & IIT Tirupati ...... b
Maps of Tirupati with important contacts ...... e
e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Welcome note: Director, IISER Tirupati
The 7th Topical Conference of the Indian Society of Atomic and Molecular Physics is being jointly hosted by the IISER Tirupati and the IIT Tirupati. Both these institutions began functioning with the first batch of students admitted from August 2015. It is thus a matter of great pride that in just a very few years, we are able to jointly organize a major conference of the ISAMP in our institutions. It is most appropriate that our first joint conference is in the very fundamental field of atomic and molecular physics which developed hand-in-hand with the quantum theory in the 20th century. This field continues to provide an arch over all of the basic sciences. Developments in this field continue to provide breakthroughs in both basic and applied sciences. Atoms and molecules provide the basic building blocks of all inorganic and even biological species. The physics of these constituents is very challenging since all fundamental processes are governed by quantum theory and relativistic mechanics. Studies in these areas have also led to major breakthroughs in new materials, including new states of matter such as the Bose-Einstein Condensates. Advanced topics in the quantum collision physics and spectroscopy will be dealt with at the ISAMP-TC7. Among many advanced topics, the conference will also address fundamental ultrafast processes including at the attosecond time-scale. It is heartening that experts from near and far parts of India, and also from many other parts of the world from the far East, to the far West, will be presenting their research works. A very good number of young researchers are also at this conference presenting their results. They will take home new ideas and provide leadership in the years and decades to come. This symposium jointly organised by IISER and IIT at Tirupati will be prelude to jointly organising meetings in other areas as well. I wish the conference every success.
Professor K. N. Ganesh Director, Indian Institute of Science Education and Research Tirupati
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e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Welcome note: Director, IIT Tirupati
I am very happy that our two new institutions – IISER Tirupati and IIT Tirupati are jointly hosting the 7th edition of the Topical Conference of the Indian Society of Atomic and Molecular Physics. Both our institutions have the great advantage of leveraging each other’s strengths and resources with the shared legacy that we have including – co-location (permanent campuses located 3 km apart), common foundation stone ceremony, launch of academic programs in August 2015 etc. Tirupati is developing as an education hub, and as a smart city. It is most appropriate that the two leading science and technology institutions in the region have come together to jointly host the Conference. Breakthroughs in technology can come only from innovative engineering, which in turn can only be enabled by advances in fundamental sciences. Computing, networking, data storage and retrieval, communication engineering, as well as the necessity to have sustainable environment friendly ecosystem requires new engineering materials, and also new processes. These can only be discovered and invented in the research laboratories in the field of basic sciences. The field of atomic and molecular physics provides the fundamental laboratory from which many innovations have been made, and tested, before new materials and processes could be scaled up for fruitful technology. The response that this conference has got is awesome. It has attracted distinguished scientists from within India and from many countries in the world. These include many world leaders in the field working in frontier research areas. Many young researchers from all parts of the country are coming for this conference, and they will present their own research, and also take back new ideas to work on. Some of these may provide important breakthroughs for engineering and technology. I join the organizing committee members in welcoming the conference delegates to Tirupati and our institutions. I wish the conference a great success.
Professor K. N. Satyanarayana Director, Indian Institute of Technology Tirupati
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e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Welcome note: President, ISAMP
Dear Members of the Society and Delegates, It is with great pleasure that I welcome you all to the seventh Topical Conference of the Society. The topical conferences began as small affairs, with a somewhat regional flavour, and over the years have grown in popularity, and have also seen participation of delegates from abroad. I trust that the current conference will meet or exceed your expectations as to the quality of the contributions and the spectrum of colleagues that you will be meeting. The topics of this conference are a good reflection of the gradual change in the focus of atomic and molecular physics research. You will also notice that participants in this conference are a healthy mix of junior and senior colleagues. We have tried our best to support the participation of students in this conference. IISER Tirupati and IIT Tirupati came to be the choice of venue for this meeting largely thanks to the initiative of Prof P C Deshmukh, who first proposed the plan. My own close association with IISER Tirupati bolstered it and the proposal got a decisive boost with the financial and Institutional support from Director, IISER Tirupati, Prof K N Ganesh, and Director, IIT Tirupati, Prof K N Satyanarayana. This conference happens to be the first national conference to be held here, and will therefore occupy a special place in the history of IISER Tirupati and IIT Tirupati. On behalf of the Society I thank both Directors and the faculty and staff of these Institutions for their whole-hearted support to the organisation of the conference. Welcome once again, and enjoy the conference!
Bhas Bapat President, ISAMP
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e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Welcome note: Conveners, ISAMP-TC7
We are delighted that the ISAMP TC7 has come to our sister institutions, the IISER and the IIT, at Tirupati. Thank you very much for coming from all over India, and also for coming from distant parts of the world. We are really extremely happy to have you here. We shall have 53 talks at the conference, but some of these will be in parallel sessions, so we urge you to go through the program schedule in advance and plan which talks you wish to attend. On each of the three days of the meeting, we shall have a poster session between lunch break and the tea break. This provides for extended periods for the poster sessions, overlapping with the lunch and the tea break. It will be great if delegates go back refreshed from this conference with some new research ideas which we hope will come out of the discussions. In order that the research work you would present at the conference gets into scientific literature, we have arranged for the proceedings of ISAMP-TC7 to be published as SPRINGER CONFERENCE PROCEEDINGS. Publishing in this special volume will make your work accessible to researchers in the years come. ISAMP-TC7 has become possible because of the generous support and guidance from Professor K. N. Ganesh (Director, IISER T) and from Professor K. N. Satyanarayana (Director, IIT T). Very many staff and faculty members at the IISER-T and the IIT-T have put in huge effort in organizing fine details with regard to various arrangements. Lapses however will be found, and these can be easily traced to the two of us. The members of the organizing committee are listed in this e-Book, and we have no words to thank them. Even if it will be unfair to mention only one of them, we wish to place on record our gratitude and admiration to Dr. S. Sunil Kumar, the Conference Secretary, for superb coordination of all activities. We are also very grateful to NPTEL for video- recording the two keynote addresses, by Professor Anatoli Kheifets (Theory) and Professor E. Krishnakumar (Experiment). These talks will remain accessible from the NPTEL web archives. Thank you all very much, and wish you all happy times in Tirupati.
Pranawa C. Deshmukh and Bhas Bapat Joint Conveners, ISAMP-TC7
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e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Indian Society of Atomic & Molecular Physics (ISAMP)
A brief history & objectives
In 1981, a group of Scientists working in Atomic and Molecular Physics in India convened a meeting in Gandhinagar, Gujarat with an aim to form a registered society with the objectives as stated below: • To encourage the study of all aspects of Atomic and Molecular Physics and help towards the advancement, dissemination and application of the knowledge of Atomic and Molecular Physics. • To promote active interaction among all persons, bodies, educational and research institutions and industries interested. • To issue such publications (e.g. newsletters, reports, bulletins, journals incorporating research and teaching ideas, reviews, new developments etc.) from time to time. • To hold periodic scientific meetings in Atomic and Molecular Physics in different parts of the Country. • To hold and sponsor topical meetings along with similar organizations and also to participate in holding International Meetings in India. • To encourage coordinated research programmes among Atomic and Molecular Physicists in India and Exchange of research personnel between research institutions and Universities in India. • To keep liaison with other atomic and molecular physics societies of the world. • To institute lectures, prizes and fellowships. • To secure grants, funds and endowments and administer the same for the furtherance of the above any or all aims and objectives. Executive Committee of the ISAMP
President: B. Bapat, IISER Pune Vice-president: B. N. Rajashekhar, BARC, Mumbai Secretary: M. Vinodkumar, VP & RPTP Science College, Vallabh Vidyanagar Treasurer: S. B. Banerjee, PRL, Ahmedabad Ex-officio member: L. C. Tribedi, TIFR, Mumbai Members: A. Shastri, BARC, Mumbai T. Ahmed, AMU, Aligarh C. P. Safvan, IUAC, New Delhi T. K. Mukherjee, Narula Institiute of Technology, Kolkata
Detailed information about the ISAMP can be found at the website: https://www.prl.res.in/~isamp/.
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Conferences Organized by ISAMP
National Conferences on Atomic and Molecular Physics (NCAMP) (Known as Workshops till 1993 BARC conference)
Year Hosted by
1976 PRL, Ahmedabad 1978 Visva-Bharati, Santiniketan 1980 CCSU, Meerut 1982 Dec IACS, Kolkata 1984 Dec TIFR, Mumbai 1986 Dec BHU, Varanasi 1988 AMU, Aligarh 1990 University of Hyderabad 1993 Mar BARC, Mumbai 1995 Mar CCSU, Meerut 1996 IIT Madras, Chennai 1998 MLSU, Udaipur 2000 IACS, Kolkata 2003 Feb Visva-Bharati, Santiniketan 2004 Dec PRL, Ahmedabad 2007 Jan TIFR, Mumbai 2009 Feb IUAC, New Delhi 2011 Feb Karnatak University, Dharwad 2012 Dec IISER Kolkata 2014 Dec IIST, Thiruvananthapuram 2017 Jan PRL, Ahmedabad
ISAMP Topical Conferences
2005 Dec IACS, Kolkata Electron Processes in Atoms and Molecules 2008 Jan SP University, Vallabh Vidyanagar Electron Collisions in Atoms and Molecules 2010 Feb RRCAT, Indore Synchrotrons for AMP 2012 Feb University of Hyderabad Lasers in AMP 2013 Nov IPR, Gandhinagar (St Laurn Hotel) Atomic Processes in Plasmas 2016 Jan ISM Dhanbad Charged Particle Collisions and Electronic Processes in Atoms, Molecules and Materials
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7th Topical Conference of the ISAMP (ISAMP-TC7)
Conveners
• Deshmukh, P. C. (IIT Tirupati & IISER Tirupati) • Bapat, Bhas (IISER Pune & IISER Tirupati)
Conference Secretary
• Sunil Kumar, S. (IISER Tirupati)
Advisory Committee
• Ganesh, Krishna N. (IISER Pune & IISER Tirupati) • Krishnakumar, E. (TIFR, Mumbai) • Rajashekhar, B. N. (BARC, Mumbai) • Satyanarayana, K. N. (IIT Tirupati) • Srivastava, Rajesh (IIT Roorkee) • Subramanian, K. P. (PRL, Ahmedabad) • Tribedi, Lokesh (TIFR, Mumbai)
Scientific Advisory Committee
• Bapat, Bhas (IISER Pune) • Bhatt, Pragya (IUAC, New Delhi) • Deshmukh, P. C. (IIT Tirupati) • Mukherjee, Tapan Kumar (Narula Institute of Technology, Kolkata) • Rajashekhar, B. N. (BARC, Mumbai) • Rangwala, Sadiq (RRI, Bengaluru) • Safvan, C. P. (IUAC, New Delhi) • Satyajit, K. T. (Amrita University, Coimbatore) • Shastri, Aparna (BARC, Mumbai) • Singh, Angom D. K. (PRL, Ahmedabad) • Subramanian, K. P. (PRL, Ahmedabad) • Sunil Kumar, S. (IISER Tirupati) • Vinodkumar, Minaxi (VP & RPTP Science College, Vallabh Vidyanagar)
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Organising Committees
Sl. No. Name of the Committee Members / Coordinators Institute 1 Reception 1. Jessy Jose (Coordinator) IISER 2. Raghunath Ramabhadran (Coordinator) IISER 3. Rajib Biswas (Coordinator) IIT Members 1. Chaman Mehta IISER 2. V. Nikhilasri IISER 3. Salvi M. IISER 4. Veena P. IISER 5. Deepu Damodar IISER 6. Bharathi K. IISER 7. Mohana IIT 8. Poornashri IIT 2 Hall Management 1. Shibdas Banerjee (Coordinator) IISER 2. Pankaj Kumar (Coordinator) IISER 3. Arun Manna (Coordinator) IIT 4. Rudra Sekhar Manna (Coordinator) IIT Members 1. Chaman Mehta IISER 2. Antony Joe IISER 3. V. Srikanth IISER 4. K. Sivakumar IISER 5. Satish Jadhav IISER 6. Sureshkumar C. IISER 7. Jagadeesh IIT 8. Senthil IIT 9. Ramesh Krishnan IIT 10. T. T. Mani IIT 3 Poster Sessions 1. Ankur Mandal (Coordinator) IISER 2. Raghunath Ramabhadran (Coordinator) IISER 3. Debasish Mondal (Coordinator) IIT 4. Rajib Biswas (Coordinator) IIT 5. Poornasri (Coordinator) IIT Members 1. Chaman Mehta IISER 2. Deepu Damodar IISER 3. V. Nikhilasri IISER 4. Salvi M. IISER 5. Sureshkumar C. IISER 6. Udayakumar IIT 7. Sanyasi Naidu IIT
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4 Transport 1. Lakshmana Rao (Coordinator) IISER 2. Gopinath Purushothaman (Coordinator) IISER 3. Koteswara Rao (Coordinator) IIT Members 1. Inderpreet Singh Kohli IISER 2. Kolli V. V. Nagarjun IISER 3. Ramesh Yadav IISER 4. N. Dileep Kumar IISER 5. Midhun Kumar IIT 5 Accommodation 1. Pankaj Kumar (Coordinator) IISER 2. Shibdas Banerjee (Coordinator) IISER Members 1. Inderpreet Singh Kohli IISER 2. Dattaprasad Gavde IISER 3. P. M. Azad IISER 6 Catering services and 1. Soloman Raju (Coordinator) IISER House Keeping 2. Raju Mukherjee (Coordinator) IISER 3. Rajib Biswas (Coordinator) IIT 4. Debasish Mondal (Coordinator) IIT 5. Koteswara Rao (Coordinator) IIT Members 1. Dattaprasad IISER 2. K. Ramesh IISER 3. M. Vamsidhar IISER 4. Ramji IIT 5. Gopal IIT 7 Computer support and 1. Chitrasen Jena (Coordinator) IISER WiFi services 2. Ankur Mandal (Coordinator) IISER Members 1. V. Srikanth IISER 2. Satish Jadhav IISER 3. T. T. Mani IIT 4. Senthil IIT 5. Lokesh IIT 8 Medical 1. Suchi Goel (Coordinator) IISER Support 2. Arunima Banerjee (Coordinator) IISER 3. Kalpana (Coordinator) IIT Members 1. Nimmy K. Prasad IISER 2. Pushpa IIT 9 Finance / Budget 1. S. Sunil Kumar (Coordinator) IISER 2. Rajib Biswas (Coordinator) IIT 10 Program Committee 1. S. Sunil Kumar (Coordinator) IISER 2. Ankur Mandal (Coordinator) IISER
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List of Abstracts
Keynote Addresses
Authors Title of the Abstract ID Page
A. Kheifets Attosecond-Time resolved studies of atomic IB004 2 and molecular photoionization: What have we learned from them?
E. Krishnakumar Electron-Molecule Resonances IA016 3
Invited Talks
Authors Title of the Abstract ID Page
R. Srivastava Characterization of inert gas plasma through IA001 5 relativistic electron excitation cross-sections
C.C. Montanari* & The shellwise local plasma approximation, a IA002 6 J.E. Miraglia many electron model for ion-matter inelastic collisions
T. Nandi Influence of strong force on electromagnetic IA003 7 interactions
H. Tanuma*, Laboratory Experiments of Solar Wind IA004E 8 N. Numadate, Charge Exchange and Related Atomic K. Shimada et al. Processes
M.N.R. Ashfold*, лσ*-state mediated bond fission: IA005F 9 M. Bain, Determining absolute branching fractions for C.S. Hansen et al. competing photoinduced bond fission processes
A. Dubey, Elastic Scattering of H Atom by C60 and IA006B 10 S. Agrawal, Kr@C60: Calculation of Total Cross Section T.R. Rao & J. Jose* and Time-Delay
R.K. Kushawaha Photoionization of polyatomic molecules: IA007E 11 multi-slits type interferences, molecular fragmentation and ultrafast dynamics
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Authors Title of the Abstract ID Page
L. Natarajan Probing quantum effects via X-ray IA008 12 spectroscopy
H. Chakraborty The Fullerene molecule: a super-attractive IA009B 13 object for new spectroscopy
R. Gopal, A. Sen, …, A three-dimensional ion imaging IA010 14 V. Sharma* spectrometer for studying photo-induced fragmentation in small molecules
G. Aravind* & Collision-induced dissociation of anions of IA011 15 R. Chacko astrophysical interest
T. Rajagopala Rao Quantum symmetry effects and isotopic IA012 16 effects in oxygen exchange reactions
S. Gordon, J. Zhou, Merging, splitting, orienting – towards IA013 17 S. Tanteri, ultracold stereodynamics N. Gkogkoglou, & A. Osterwalder*
S. Fritzsche Excitation and ionization of atoms by twisted IA014 18 light
J. Tennyson Low temperature chemistry using the R- IA015 19 matrix method
D. Nandi Dissociative electron attachment and dipolar IA017 20 dissociation dynamics probed by velocity slice imaging
S. Krishnan Electron dynamics in small atomic IA018 21 aggregates at He nanodroplets: multicoincidence spectroscopy
J.A. Lopez-Domınguez*, Multichannel photoionization of polyatomic IA019 22 M. Klinker, non-linear targets within the XCHEM C. Marante et al. approach: the H2O case study
L.C. Tribedi Angular asymmetry of electron emission and IA020 23 ionization dynamics
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e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Authors Title of the Abstract ID Page
Y. Azuma Post Collision Interaction (PCI) Recapture of IA021 24 Photoelectrons into Rydberg Orbitals: Electrons Playing Tag at Threshold
C. Christophe Dosimetry of ionizing radiations in IA022 25 biological tissues: Importance of calculations at a microscopic scale
Y. Khajuria Spectroscopic studies and quantum chemical IA023 26 investigations of (3, 4−dimethoxybenzylidene) propanedinitrile
M. Krishnamurthy Acceleration of neutral atoms in laser IA024 27 produced plasmas
K.P. Subramanian*, LTE condition validation by plume IA025E 28 B.G Patel & P. Kumar characterization in laser produced plasmas
M.F. Ciappina Attosecond Physics at the Nanoscale IB001 29
H.R. Varma Wigner photoionization time delay studies of IB002 30 the neon 2s → np autoionization resonances
R. Lucchese Aspects of single-photon ionization of IB004 31 molecules with implications for Wigner time delay and high-harmonic generation
G. Dixit*, Control of helicity of high-harmonic IB005 32 Á. Jiménez-Galán, radiation using bichromatic circularly L. Medišauskas et al. polarized laser fields
R. Bai, Quantum Hall states in optical lattices IC001 33 S. Bandopadhyay, ..., D. Angom
J. Bera, & U. Roy* Long Time Evaluation of Bose-Einstein IC002 34 Condensate in a Toroidal Trap
M. Mukherjee*, Precision measurements with trapped ions IC003D 35 D. Yum & T. Dutta
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Authors Title of the Abstract ID Page
R.Sawant, Atoms, molecules and ions in cavities ID001 36 S. Dutta, ..., & S. A. Rangwala*
V. Sudhir*, Quantum measurement and control of a ID002 37 D. Wilson, mechanical oscillator S. Fedorov et al.
P. Chakraborty Ion-beam synthesis of metal quantum dots in ID003 38 glasses for nonlinear photonic Applications
T. Azuma Recurrent fluorescence observed with an ion ID004 39 storage ring
A. Bhowmik & Tunable magic wavelengths of cooling and ID005 40 S. Majumder* trapping with focused LG beam
A. Wolf Fast Ion Beams in a Cryogenic Storage Ring: IE001 41 Collisions and Internal Excitations
M. Schmidt* & Elaborated Electron Beam Ion Sources for IE002 42 G. Zschornack AMO Physics and Laboratory Astrophysics
B.N. Rajasekhar* & Design of an experimental facility for IE003 43 Asim Kumar Das Molecular Science research using UV-VUV and soft X-ray photons
C.P. Safvan Molecular Physics facilities at IUAC IE004 44
U.R. Kadhane Plasma and beam diagnostics for electric IE005 45 propulsion research
S. Son Ultrafast ionization and fragmentation IF001 46 dynamics of molecules at high x-ray intensity
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Contributed Talks
Authors Title of the Abstract ID Page
n+ S. Kumar*, Dissociation dynamics of N2 cations (n=1- CA001 48 S. Prajapati, 2) and kinetic energy release study in the B. Singh, et al. collision of 3.5 keV electron with nitrogen molecule
K. Saha, Ultraslow isomerization in photoexcited gas CA003 49 - V. Chandrasekaran, phase C10 O. Heber et al.
H. Kumar, Fragmentation dynamics of multiply charged CA006 50 P. Bhatt, OCS C.P. Safvan et al
S. Mandal, Isomerization of Acetylene doped in He CA035 51 R. Gopal, nanodroplets by EUV synchrotron radiation S. Krishnan et al
A. Shastri*, Vacuum ultraviolet photoabsorption CA049 52 A.K. Das & spectroscopy of anisole B.N. Raja Sekhar
S. Soumyashree*, Elemental analysis using Laser Induced CA051E 53 P. Kumar, Breakdown Spectroscopy R.K. Kushawaha et al.
V. Pramod Majety* & Multielectron effects in strong field CB003 54 A. Scrinzi ionization of few electron molecules
U. S. Sainadh*, H. Xu, Tunneling delays in strong field ionization of CB005 55 X. Wang et al. atomic hydrogen
A. Acharya*, PC based Acousto Optic Modulator Driver CC001 56 R. B. Reddy, for Cold Atom Interferometer M. Bajaj et al
N. Kundu* & U. Roy Two Components Bose-Einstein Condensate CC004 57 in a Frustrated Optical Lattice
P. Rajauria* & Non-autonomous matter-waves in a quasi- CC007 58 T. S. Raju one-dimensional waveguide geometry
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Posters
Authors Title of the Abstract ID Page
B. Singh, S. Prajapati, Measurement of the angular distributions of CA002 60 S. Kumar et al. thick target bremsstrahlung produced by 10- 25 keV electrons incident on thick Ti & Cu pure elements.
Priti, L. Sharma & Xenon Plasma Modeling with Relativistic CA004 61 R. Srivastava Fine Structure Cross Sections
A. Mandal & SOIAIC effect on Wigner-Eisenbud-Smith CA005B 62 P.C. Deshmukh time delay: Xe 4d photoionization
A. Husan, S. Jabeen & Study of the excited even configuration of Cs CA007A 63 A. Wajid VII
S.Gupta, L. Sharma & Electron-impact excitation of Xe+ ion and CA008 64 R. Srivastava polarization of subsequent emissions
A. Mandal & Wigner-Eisenbud-Smith time delay in CA009B 65 P. C. Deshmukh photoionization of n f subshell: angle and spin resolved study
A. Dora & J. Tennyson Potential energy curves of the higher lying CA010 66 resonances in electron-CO scattering
B. Bapat, D. Sharma, Orientation effects in ionisation of CO by CA011 67 A. Kumar et al proton and ion impact
C. C. Montanari & The IAEA database for stopping power, CA012 68 P. Dimitriou trends in the energy loss experimental research
C. C. Montanari & Energy loss of low energy protons and CA013 69 J. E. Miraglia antiprotons in metals
R. Bhavsar, Y. Thakar, & Electron interaction scattering cross sections CA014 70 C. Limbachiya of Astromolecules
Y. Thakar, R. Bhavsar, & Electron interaction scattering cross sections CA015 71 C. Limbachiya of Biologically relevant molecule
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Authors Title of the Abstract ID Page
D. Prajapati, H. Yadav, & Electron Induced chemistry of CA016 72 M. Vinodkumar Chlorobenzene
S. K. Kumar, Optical breath gas sensing using UV-VUV CA017 73 B. N. Rajasekhar & absorption spectroscopy A. K. Das
A.M.P. Mendez, Fully relativistic structure calculations of CA018 74 D.M. Mitnik, & heavy targets for inelastic collisions C. C. Montanari,
M. Kumar, R. Singh & Kinetic energy release distribution in CA019 75 S. Pal electron dissociative ionization of CO2
A. K. Das, VUV Spectroscopy of Diethyl Carbonate CA020 76 S. Krishnakumar & B. N. Rajasekhar
R. Bala, H. S. Nataraj & Ab initio calculations of spectroscopic CA021 77 M. Abe parameters of HfH+ and PtH+
M. R. Parida & Ultrafast spectroscopy of perovskite CA022 78 O. F. Mohammed interfaces
D. Chakraborty, P. Nag, Absolute dissociative electron attachment CA023 79 & D. Nandi cross section measurement studies for difluoromethane
A. Rashid & The spectrum of quadruply ionized mercury: CA024 80 A. Tauheed Hg V
A. Ganesan, Xe 5s Photoionization near the Second CA025 81 G.B. Pradhan, Cooper Minimum using RMCTD P.C. Deshmukh
S.Singh, P. Verma, & Positron collision dynamics for C2-C3 CA026 82 V. Singh hydrocarbons
M. Vinodkumar, Dissociative electron attachment study of di CA027 83 H. Yadav, & & tri atomic molecule P.C. Vinodkumar
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Authors Title of the Abstract ID Page
H. Yadav, Electron impact scattering studies of CA028 84 M. Vinodkumar, Halomethane (CH3X, X = F, Cl, Br, I) C. Limbachiya et al.
S. Bharti, P. Malkar, Electron scattering from endohedrally CA029D 85 L. Sharma et al. confined Ca atoms
K. Chakraborty, Molecular effects in L shell ionization of Au CA030 86 R. Gupta, and Bi by slow Ag ions Ch.V. Ahmad et al.
K.K Gorai, VUV Spectroscopy of Dodecane Molecule CA031 87 P.J. Singh, using synchrotron radiation A. Shastri et al
R. Gupta, Detecting the elemental constitution of CA032 88 Ch. V. Ahmad, environmental samples of Delhi and K. Chakraborty et al surrounding regions using XRF spectroscopy
S. Kumar, S. Kumar, Characterization of thin aluminized CA033 89 D. K. Swami et al polypropylene backed atomic targets using 2 MeV He+ Ions
S. Kumar, S. Kumar, L shell x-ray production in ultra-thin 76Os CA034 90 D. K. Swami et al. using 4-6 MeV/u fluorine ions.
P. Modak, V. Patel, Ionization cross section of water clusters CA036 91 n H. Tomer et al. ((H2O) ,n=1-4) by electron impact
P. Sharma & T. Nandi Disentangling charge exchange processes in CA037 92 bulk from surface
R. Singh, M. Kumar, Determination of energy and angle CA038 93 N. Kumar & S. Pal dependent electron ionization cross sections for methylamines
A. Naratajan & Kα X-Rays from Variously Ionized Iodine CA039 94 L. Natarajan
S. Ankita & The Spectrum of Doubly Ionized Silver: Ag CA040 95 A. Tauheed III
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Authors Title of the Abstract ID Page
A. Sen, Study Molecular Dissociation Dynamics CA041 96 A.S. Venkatachalam, using Velocity Map Imaging S. R. Sahu et al.
P.J. Singh, A.K. Das, Synchrotron based VUV spectroscopy of CA042 97 K.K. Gorai et al. dimethylacetamide
N. Sinha, D. Patel & Positron Scattering Cross Sections for CA043 98 B. Antony Methyl Halides
A. Zainab & Energy levels and classified lines in the third CA044 99 A. Tauheed spectrum of gold: Au III
S. Ghosh, B. Halder & Phase Space Structures and Isotope CA045 100 U. Roy Separation of Bromine Molecules
A. Wajid, S. Jabeen & Isoelectronic Energy Levels of Xe-like Ions: CA046 101 A.Husain La IV- Ce V
S. Mukund, S. Laser-induced fluorescence spectroscopy of CA047 102 Bhattacharyya & jet-cooled LaNH: Observation of (0,0) C2∏ - S.G. Nakhate Χ2Σ+ transition
J. Singh, M. Khamesian Theoretical method to study electron-impact CA048 103 & V. Kokoouline rotational excitation of molecular ions
N. B. Ram, S. G. Walt, Imaging electron-nuclear dynamics in strong CA050B 104 M. Atala et al field rescattering
N. Uddin, P. Verma & Electron scattering total ionization cross CA052 105 B. Antony section of H2CCCC: A cumulene carbene detected in interstellar medium
P. K. Najeeb, Structural stability of polycyclic aromatic CA053 106 M. V. Vinitha, hydrocarbons and polycyclic nitrogen A. Kala et al heterocycles under charged particle collisions
M.V. Vinitha, Collisional isomerisation between CA054 107 P.K. Najeeb, naphthalene and azulene due to energetic K. Anudit et al proton
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e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Authors Title of the Abstract ID Page
M. Nrisimhamurty, Two- and three-body dissociation dynamics CA055 108 L.C. Tribedi & D. Misra of H2O2
S. Banerjee, Effects of interchannel coupling on angular CB001 109 H.R. Varma & distribution of photoelectrons and on time P.C. Deshmukh delay in the autoionization regions of Neon 2s → np resonance series
A. Jain, R. Heider, Attosecond-Streaking Spectroscopy on a CB002E 110 M. Wagner et al Liquid-Water Microjet
S. Banerjee, Photoionization dynamics of Ar@C 540 CB004 111 A. Thuppilakkadan, H. R. Varma et al
S. Saha, J. Jose & Shape resonance induced Wigner time delay CB006 112 P.C. Deshmukh in atomic photoeffects
S. Saha, J. Jose & Influence of SOIAIC in photodetachment CB007 113 P.C. Deshmukh and photoionization time delays near the centrifugal barrier shape resonance
A. Thuppilakkadan, Effect of model potentials (smooth Vs hard) CB008 114 S. Saha, J. Jose et al on the Wigner time delay of H@C60 Photoionization
S. Bhushan & A Two Dimensional Magneto Optical Trap CC002 115 R.K. Easwaran with High and Tunable Optical Depth for Slow Light Applications
S. Modak, P. Das, & Quantum State Transfer through Coherent CC003 116 P. K. Panigrahi Atom-Molecule Conversion in Bose-Einstein Condensate
J. Bera, A.Q. Batin, Breathing Dynamics of Ultracold Atoms in a CC005 117 S. Ghosh et al Vibrated Optical Lattice
V. U. Kumar & A pedagogical simulation of the Aharonov- CC006D 118 P. C. Deshmukh Bohm effect
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e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018
Authors Title of the Abstract ID Page
S. Dutta & Cooling of trapped ions with a tiny cloud of CD001 119 S. A. Rangwala ultracold atoms: the role of resonant charge exchange
D.K. Bayen & Quantum dynamics and frequency shift of a CD002 120 S. Mandal Driven multi-photon anharmonic oscillator
S. Kumar, S. Ringleb, High-intensity laser ion experiments in CD003 121 N. Stallkamp et al Penning Trap
Prakash, D. Datar, Non-linear Axial Oscillations of an Electron CD004 122 B.M. Dyavappa et al plasma in a Penning Trap
R. K. Gangwar, A Novel Cooling Process Using CD005 123 K. Saha, O. Heber et al Autoresonance in an Electrostatic Ion Beam Trap
R. Chacko, Development of a 22-pole radio-frequency CE001 124 P. C. Deshmukh & ion-trap experimental set-up to study ion- G. Aravind atom and ion-photon collisions of astrophysical interests
A.Sharma, M. Leyser, Towards a search for Dark Matter candidates CE002 125 A.V. Viatkina et al using atomic Dysprosium
U. Momeen & J. Hu Development of nanoscale magnetometry CF001 126 using nitrogen-vacancy center in diamond
J. Hu & U. Momeen Novel tunable near field broadband CF002 127 microwave antenna designs for nitrogen- vacancy center in diamond
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Abstracts of Keynote Addresses ISAMP TC-7, 6 8 January, 2018, Tirupati IB004 Kheifets − Attosecond-Time resolved studies of atomic and molecular photoionization: What have we learned from them?
1 Anatoli Kheifets∗
∗ Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200, Australia
Time resolved studies of atomic photoioniza- tion with various pump-probe techniques such as References attosecond streaking [1] or RABBITT [2], or self-referencing techniques like attoclock [3] [1] M. Schultze et al. Science, 328 1658, 2010. opened up a new and rapidly developing area [2] K. Klunder et al. Phys. Rev. Lett., of research collectively termed attosecond 106 143002, 2011. chronoscopy [4]. The attosecond streaking and RABBITT measurements return the [3] P. Eckle et al. Science, 322 1525, 2008. photoelectron group delay which is related to [4] R. Pazourek, S. Nagele, and J. Burgd¨orfer. Rev. the photoelectron phase and its energy Mod. Phys., 87 765, 2015. derivative known as the Wigner time delay [5] J.M. Dahlstr¨om, D. Gu´enot, K. Kl¨under, M. Gis- [5]. These studies bring one step closer what selbrecht, J. Mauritsson, A. L Huillier, A. Ma- had been dreamed of as a complete pho- quet, and R. Ta¨ıeb. Chem. Phys., 414 53, 2012. toionization experiment. The attoclock mea- [6] Alexandra S. Landsman and Ursula Keller. At- surement can be related to the tunneling time, tosecond science and the tunneling time problem, i.e. the time photoelectron spends under the Physics Reports, 547 1, 2015. barrier in a classically inaccessible region. The [7] I. Jordan, M. Huppert, S. Pabst, A. S. Kheifets, new measurements reopened decades-long D. Baykusheva, and H. J. W¨orner. Phys. Rev. debate about a finite tunneling time [6]. A, 95 013404, 2017. In this presentation, the recent theoretical [8] M. Huppert, I. Jordan, D. Baykusheva, A. von advances in evaluating the Wigner and tunnel- Conta, and H. J. W¨orner. Phys. Rev. Lett., ing times in atomic and molecular photoioniza- 117 093001, 2016. tion will be reviewed in connection with ongoing [9] J. Vos, L. Cattaneo, S. Patchkovskii, experimental activities. The following topics will T. Zimmermann, C. Cirelli, M. Luc- be highlighted. chini, A. Kheifets, A. S. Landsman, , and 1. Wigner time delay in photoionization of U. Keller. Orientation-dependent stereo free and encapsulated noble gas atoms. This Wigner time delay in a small molecule. In topic includes the relativistic effects and angu- ICOMP 14 , Budapest, Hungary, 2017. lar dependent time delay. Connection with the [10] U. S. Sainadh, H. Xu, X. Wang, Atia- recent measurements in heavy noble gas atoms Tul-Noor, W. C. Wallace, N. Douguet, [7] will be made. A. W. Bray, I. Ivanov, K. Bartschat, 2. Wigner time delay in molecular photoion- A. Kheifets, R. T. Sang, and I. V. Litvinyuk. ization [8] including the stereoscopic time delay ArXiv e-prints 1707.05445, July 2017. in heteronuclear molecules [9] [11] Lisa Torlina, Felipe Morales, Jivesh Kaushal, 3. Tunneling time measurements [10] and cal- Igor Ivanov, Anatoli Kheifets, Alejandro Zielin- culations [11] in atomic hydrogen and their im- ski, Armin Scrinzi, Harm Geert Muller, Suren plications for the finite tunneling time problem Sukiasyan, Misha Ivanov, and Olga Smirnova. In conclusion, directions of the future time re- Nat. Phys., 11 503, 2015. solved studies of atomic photoionization, includ- [12] A. S. Kheifets, A. W. Bray, and Igor Bray. Phys. ing threshold effects [12] will be discussed. Rev. Lett., 117 143202, 2016.
1E-mail: [email protected]
2 ISAMP TC-7, 6 8 January, 2018, Tirupati IA016 Krishnakumar − Electron-Molecule Resonances
1 E. Krishnakumar∗
∗ Dept. of Nuclear and Atomic Physics, Tata Institue of Fundamental Research, Homi Bhabha Road, Mumbai -400 005, India
Electron-molecule resonances, which are short- found that the energy specificity of this process al- lived excited states of molecular negative ions, have lows chemical control by bond selective fragmenta- attracted increasing attention in recent times due to tion of organic molecules. Though diverse experi- their complex dynamics as well as their role in wide mental techniques have been used to study the res- variety of practical applications. Formation and de- onances over the last few decades, recent advances cay of the resonance is the most efficient way of have provided several new insights into the dynamics converting kinetic energy into chemical energy in a of these species. This talk would provide an introduc- medium through the creation of vibrationally or elec- tion to negative ion resonances and a short overview tronically excited states, radicals and negative ions - of their importance followed by some of the signifi- all of which are chemically very active. It has been cant findings in recent times.
1E-mail: [email protected]
3 Abstracts of Invited Talks ISAMP TC-7, 6 8 January, 2018, Tirupati IA001 Srivastava − CHARACTERIZATION OF INERT GAS PLASMA THROUGH RELATIVISTIC ELECTRON EXCITATION CROSS-SECTIONS
Rajesh Srivastava*
* Department of Physics, IIT Roorkee, Roorkee –247667 Uttarakhand, India
Topic: A- Quantum collisions and spectroscopy of atoms, molecules, clusters and ions.
There is need to develop reliable collisional pact excitation, ionization, radiative decay radiative (CR) models for inert gas plasma at along with their reverse processes such as elec- low temperature. Dominant processes involved tron impact de-excitation, three body recombi- in the plasma modeling are the electron impact nation. Rate equations for all fine structure lev- processes. Despite the large body of literature els are solved simultaneously to obtain the pop- on inert gases, there is in general serious lack of ulation of the levels through which intensities of excitation cross section data for their various different transitions are calculated and com- fine-structure transitions [1-3]. Also the grow- pared with the experimentally measured intensi- ing demand of electron-atom/ion collision data ties to fix the electron density and temperature can’t be met solely through experimental meas- of the plasma. Our detailed results for Kr and urements. Due to the complexity involved in Ar as well as Ar-O2 and Ar-N2 plasma will be dealing with the fine-structure transitions the presented discussed [2-5]. theoretical data used for plasma modeling have been obtained from empirical or simple classi- References cal methods which are not reliable. Consequent- ly, reliable fine-structure cross sections should [1] S. Wang, A. E. Wendt, J. B. Boffard, C. C. Lin, be obtained and then incorporated into the CR S. Radovanov, and H. Persing, 2013 J. Vac. Sci. model for low temperature plasmas [3]. A re- Technol. A, 31 021303 view on our CR models that we have recently [2] R. A. Dressler, Y. Chiu, O. Zatsarinny, K. developed for inert gas plasmas viz. considering Bartschat, R. Srivastava, and L. Sharma, 2009 Kr and Ar as well as their mixture with molecu- J. Phys. D. Appl. Phys., 42 185203 lar gases like O2 and N2 will be discussed [2-5]. [3] R. K. Gangwar, L. Sharma, R. Srivastava, and The required electron impact fine-structure A. D. Stauffer, 2012 J. Appl. Phys., 111 053307 excitation cross-sections of the considered inert [4] Dipti, R. K. Gangwar, R. Srivastava, and A. D. gases are obtained from the accurate fully rela- Stauffer, 2013 Eur. Phys. J. D, 67 40244 tivistic distorted wave (RDW) theory [4-7] and [5] R. K. Gangwar, Dipti, L. Stafford and R. these are incorporated in the CR model. The Srivastava, 2016 Plasma Sources Sci. Technol. model considers several electron impact fine 25 035025 structure transitions from the ground as well as [6] R. K. Gangwar, L. Sharma, R. Srivastava, and excited fine structure states. The model incorpo- A. D. Stauffer, 2010 Phys. Rev. A, 82 032710 rates various population transfer mechanisms [7] R. K. Gangwar, L. Sharma, R. Srivastava, and among fine structure levels such as electron im- A. D. Stauffer, 2010 Phys. Rev. A, 81 052707
E-mail: [email protected]
5 ISAMP TC-7, 6 8 January, 2018, Tirupati IA002 Montanari − The shellwise local plasma approximation, a many electron model for ion-matter inelastic collisions
C. C. Montanari 1, J. E. Miraglia 2
Instituto de Astronomía y Física del Espacio, CONICET and Universidad de Buenos Aires, Argentina Facultad de Ciencias Exactas y Naturales, Univerisdad de Buenos Aires, Buenos Aires, Argentina
Topic A: We present and discuss here the possibilities and ranges of validity of the shellwise local plasma approximation to deal with the inelastic collisions. This model describes the response of target bound electrons collectively by means of the dielectric formalism, considering the different subshells and binding energies. We present here our results for ionization cross sections, energy loss of ions in matter and also energy los straggling. A wide spec- trum of collisions of ions with gases and solids, atomic or molecular targets is covered, with. special attention to multielectronic relativistic targets.
The shellwise local plasma approximation (SLPA) [1] is an ab-initio model to deal with the inelastic collisions. It is a many-electron model within the frame of the dielectric formal- ism, especially suitable for multi-electronic tar- gets and intermediate to high energy collisions, in which target deep shells are involved. The SLPA describes the electronic response of each sub-shell of target electrons as a whole, includ- ing screening among electrons. This is of par- ticular interest when describing many-electron sub-shells such as 4f or 3d. The main character- istics of the SLPA are the independent-shell ap- proximation (a dielectric function for each sub- Figure 1. Energy loss of protons in solid gold. Ex- shell of target electrons, i.e. only the electrons perimental data from IAEA database [4]. of the same binding energy respond collectively to the ion perturbation and screen among them) and the inclusion of the binding energy explic- itly (not free-electron gas, but electron gas with an energy threshold). The inputs are the elec- tronic densities of the different sub-shells and the corresponding binding energies. For these reason, the model is suitable for describing atomic or molecular targets (see for example the results for water in [2] and for ZnO in [3]. We will present details of this model such as the inclusion of the charge state of the ion, the separate treatment for conduction and bound electrons in metals, or the description of relativ- istic targets. Figure 2. L-shell ionization cross sections of alphas in solid lead. Experimental data by Hardt [5]. In Fig. 1 the SLPA curve for the energy loss of protons in gold is displayed. All experimental References data is included by using the compilation by Paul at the IAEA [4]. [1] Montanari et al. (2013), Advances in Quantum Chem- In Fig. 2 we display the results for ionization istry, ed. Dz. Belkic (Elsevier), Chap. 7, pp. 165-201. of the Li subshells (2s, 2p1/2, 2p3/2). The rela- [2] Montanari et al. (2014), J. Phys. B 47, 015201. [3] Fadanelli et al (2016), Eur. Phys. J. D 70, 178. tivistic description of Pb including the spin- [4] https://www-nds.iaea.org/stopping/ orbit split is considered. [5] Hardt et al (1976) Phys Rev A 14, 137.
1 E-mail: [email protected] 2 E-mail: [email protected]
6 ISAMP TC-7, 6 8 January, 2018, Tirupati IA003 Nandi − Influence of strong force on electromagnetic interactions
T. Nandi*1
*Inter-University Accelerator Centre, JNU Campus, New Delhi110067, India.
Topic: A
The well-known disparity between the in- indeed a high density localized plasma [7]. These teraction range and coupling constant for the elec- preparatory grounds lead us to proceed for the ma- tromagnetic and strong force suggests independent jor goal. We measure the projectile K x-ray spectra treatment of the atomic and nuclear phenomena. as a function of the beam energies in small steps However, some distinct processes viz. bound-state aroun d the Coulomb barrier in different collision β-decay [1], nuclear excitation by electron capture systems and notice an unusual increase in x-ray en- [2] etc., occurring at the borderline between the ergy near the interaction barrier energies. The un- atomic and nuclear physics, provide a possibility to derlying process is found, theoretically in the sud- explore the interference between such interactions. den approximation limit, to be shakeoff of L-shell Similarly, Coulomb barrier region also may provide electrons of the projectile due to the sudden nuclear an opportunity to study the interplay between the recoil. This fact finally leads to discover the fact atomic and nuclear processes [3]. Nevertheless, no that the strong nuclear force does influence on the effort has been invested yet to study the influence atomic processes [8]. Interestingly, such phenome- of the nuclear interaction on the atomic processes at non finds significant implications in dark matter the barrier energies during the ion-atom interaction. search experiments [9] and atomic physics research We have investigated the above mentioned, at the nuclear regimes. atomic phenomena in the interface of atomic and I shall introduce the foundation of this unu- nuclear physics through experimental as well as sual topic and then the various steps in achieving theoretical routes. Earlier works in this laboratory the present goal. Finally, highlight the important indicate clearly that the shakeoff ionization is one results and then possible impacst in future applica- of the major phenomena important in this regime. tions. Accordingly, in the first step we have put certain References efforts to establish the theoretical frame works [4]. [1] J. N. Bahcall, 1961 Phys. Rev. 124 495 Side by side we develop experimental setup incor- [2] A. Palffy et al., 2006 Phys. Rev. A 73 012715 porating both atomic and nuclear tools. Next chal- [3] M. S. Freedman 1974 Ann. Rev. Nucl. Sci. 24 209 [4] P. Sharma et al. 2015 Nucl. Phys. A 941 265 lenge is to utilize the x-ray spectra in finding the [5] P. Sharma et al. 2016 Phys. Lett. A 380 182 [6] P. Sharma et al. 2017 submitted to Euro Phys. Lett. charge changing phenomenon in the bulk of the [7] P. Sharma et al. 2016 Phys. Plas. 23 083102 target foil [5] and then proceed to monitor the sur- [8] P. Sharma et at. 2017 Phys. Rev. Lett. (in Press). [9] H. Ejiri et al. 2006 Phys. Lett. B 639 218 face effects through the radiative electron capture processes [6]. Further, thorough analysis enables us to establish the fact that the beam-foil interaction is
[Type1E-mail: here] nandit [email protected] 7 ISAMP TC-7, 6 8 January, 2018, Tirupati IA004E Tanuma − Laboratory Experiments of Solar Wind Charge Exchange and Related Atomic Processes
Hajime Tanuma1, Naoki Numadate, Kento Shimada, Hirofumi Shimaya, Takuya Ishida, Takuma Kanda, Nobuyuki Nakamura∗, Kunihiro Okada†, Ling Liu‡, and Jianguo Wang‡
Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan ∗ Institute of Laser Science, The University of Electro-Communications, Chofu, Tokyo 182-0021, Japan † Department of Physics, Sophia University, Chiyoda, Tokyo 102-8554, Japan ‡ Institute of Applied Physics and Computational Mathematics, Beijing 100088, Republic of China
Topic: A&E
The soft X-ray emission observed with the through a collision cell filled with a neutral gas ROSAT all-sky survey in the 1990s found an has been analyzed by a electrostatic deflector to intensity fluctuating in cycles of 1–2 days du- obtain total charge changing cross sections. ration [1]. It was difficult to understand this 2) Emission spectra and emission cross sections: phenomenon before the mechanism of the soft Soft X-ray and extreme ultra-violet (EUV) X-ray emissions from comets has been revealed. emissions following charge exchange collisions In 1996, the ROSAT also observed the soft X- have been observed at magic angles by a silicon ray emission from the comet C/Hyakutake 1996 drift detector and a grazing incident spectrome- B2 approaching to Earth [2]. According to ter with a cooled CCD camera, respectively [5, 6]. Cravens’ suggestion, it has been recognized that 3) Observation of forbidden transitions: the soft X-ray emission stems from charge ex- He-like ions produced in collisions of H-like change collisions between the solar wind ions ions with neutral gas targets are in both sin- and the neutrals among the comet, and this glet and triplet states. Most of triplet states phenomenon is called “Solar Wind Charge eX- will transfer to the 1s2s 3S, which has a long change” (SWCX) [3]. In analogy to this, it was lifetime, via cascade transitions. To observe the proposed that the soft X-ray background radia- forbidden transition directly, we have developed tion with fluctuating intensity is due to a charge- a Kingdon ion trap and have measured a pure excange of the highly charged ions in the solar spectrum of the forbidden transition of 1s2–1s2s wind with thin neutral matter within the helio- successfully [7, 8]. sphere [4]. 4) Soft X-ray emissions from 1s2snp states: In order to analyze soft X-ray emission spec- Recently, we have observed the soft X-ray tra observed with X-ray observatory satellites emissions corresponding to 1s22s–1s2snp (n = 2 quantitatively, accurate emission cross sections and 3) transitions of Li-like ions in collisions of in collisions of multiply charged ions with neu- meta-stable He-like ions, which are produced by tral atoms are required by astrophysicists. We the ECRIS, with neutral gases [9]. have a 14.25 GHz electron cyclotron resonance ion source (ECRIS) which can produce various References multiply charged ions (for example, bare, H-like, [1] Snowden S L et al. 1994 Astrophys J. 424 714 and He-like ions of C, N, and O atoms etc.) in a [2] Lisse C M et al. 1996 Science 274 205 plasma of about 106 K and beam lines for colli- [3] Cravens T E 2000 Astrophys. J. 532 L153 sion experiments between multiply charged ions [4] Fujimoto R 2007 Publ. Astron. Soc. Japan 59 and neutral gases with solar wind speed of 300– S133 800 km/s which corresponds to a kinetic energy [5] Kanda T et al. 2011 Phys. Scr. T144 014025 range of 0.5–3.3 keV/u. [6] Shimaya H et al. 2013 Phys. Scr. T156 014002 Using this multiply charged ion beam facil- [7] Numadate N et al. 2014 Rev. Sci. Instrum. 85 ity, we have been performing the following ex- 103119 periments in this decade: [8] Numadate N et al. 2017 Nucl. Instrum. Meth. B 1) Total charge exchange cross sections: 408 114 Charge state distribution after passing [9] Numadate N et al. to be submitted
1E-mail: [email protected]
8 ISAMP TC-7, 6 8 January, 2018, Tirupati IA005F Ashfold − σ*-state mediated bond fission: Determining absolute branching fractions for competing photoinduced bond fission processes.
Michael N.R. Ashfold,1 Matthew Bain, Christopher S. Hansen and Rebecca A. Ingle
School of Chemistry, University of Bristol, Bristol, U.K. BS8 1TS
Topic: A (or F)
Heterocycles are common chromophores in 4. Demonstrate how these recent advances in the nucleobases and the aromatic amino-acids photofragment ion imaging can be used to de- that dominate the near ultraviolet (UV) absorp- termine absolute branching fractions for com- tion spectra of many biological molecules. peting bond fission processes, e.g. of the rival * excitations are responsible for the strong C–S bonds in tert-butylmethylthioether. UV absorptions, but such molecules also pos- sess excited states formed from * electron promotions. The * states typically have much smaller absorption cross-sections, but can have profound photophysical importance. We have used photofragment translational spectroscopy (PTS) methods and complementary ab initio calculations to explore *-state mediated bond fission following UV excitation of many such heteroatom containing molecules in the gas phase, and ultrafast pump-probe studies to in- 2 vestigate analogous processes in a number of Figure 1. Images of the Br( P3/2) atoms formed by different solvents [1]. photolysis of gas phase 2-bromothiophene molecules This presentation will address near UV pho- at 266.6 nm (above) and 244.9 nm (below). The toinduced S–H and S–C bond fissions in thio- electric vector of the photolysis laser radiation is phenols, thioanisoles and thiophenes. We will: aligned vertically, and the image radii are propor- 1. Summarize the extent to which photophys- tional to the fragment recoil velocity. The use of ical insights gained from collision-free gas more energetic photons yields slower Br atoms [4]. phase photolysis studies of thiophenols and thi- oanisoles can guide our interpretation of ultra- References fast pump-probe transient absorption studies of [1] M.N.R. Ashfold, et al., 2010, Phys. Chem. the UV photofragmentation dynamics of similar Chem. Phys. 12, 1218. molecules in solution and vice versa [2]; [2] S.J. Harris, et al., 2013, Phys. Chem. Chem. 2. Show how such solution phase studies of- Phys. 15, 6567. fer a route to exploring *-state mediated ring- [3] M.N.R. Ashfold, et al., 2017, Annu. Rev. Phys. Chem. 68, 63. opening of heterocycles like thiophenes [3,4]; [4] M.N.R. Ashfold, et al., 2017, J. Phys. Chem. Letts., 3. Review recent attempts to study the dy- 8, 3440. namics of photoinduced ring-opening processes [5] B. Marchetti, et al., 2015, J. Chem. Phys. 142, in the gas phase, using both traditional (Fig. 1) 224303. [5] and novel multimass-detection, universal- [6] R.A. Ingle, et al., 2017, J. Chem. Phys. 147, 013914. ionization, velocity-map imaging [6] methods.
9 ISAMP TC-7, 6 8 January, 2018, Tirupati IA006B Jose −
Elastic Scattering of H Atom by C60 and Kr@C60 : Calculation of Total Cross- Section and Time-Delay
KM. AKANKSHA DUBEY*, SHWETA AGRAWAL†, T. RAJGOPALA RAO†, JOBIN JOSE*1
* Department of Physics, Indian Institute of Technology Patna, Bihta – 801106, Bihar, India † Department of Chemistry, Indian Institute of Technology Patna, Bihta – 801106, Bihar, India
Top: A, B
Total scattering cross-section and time-delay (b), the resonance energies are shifted further. for elastic collision of H atom with C60 and The energy range for resonances here is Kr@C60 have been studied theoretically in this between 0.17 to 0.19 a. u. work. We have taken primarily two cases-(a) H atom passing through hexagonal and (b) H atom Further, time-delay calculations have been passing through pentagonal ring of C60. Both performed based on Wigner-Eisenbud time- the cases are compared and contrasted. We have delay theory [6]. We observe that l=0 partial thus tried to illustrate the contribution of con- wave of the projectile experiences a maximum fined Kr by analyzing the results of H+C60 and time-delay of 31.0 and 23.0 pico-seconds for H+Kr@C60 scattering in each cases. case (a) and (b) respectively.
Interaction-potential for H+Kr@C60 and H+C60 are computed in each case using DFT (B3LYP) method employing-631g*-basis set of GAUSSIAN16 set of codes [1]. This potential exhibits a double-humped barrier in the region of the boundary of C60 [2]. The barrier height is distinctively more for the case (b) than that for the case (a). This result in differences in the scattering parameters of our interest: cross- section and time-delay. Time-independent Schrodinger equation has been solved numerically, using Numerov’s technique [3]. Corresponding partial phase- Figure1 Cross-section vs Energy curve for
shifts (l(E)) are determined using partial wave- H+Kr@C60 collision for case (a) (Top axis) and case analysis of scattering theory in order to obtain (b) (Bottom axis). the total cross-section. The total scattering cross-section for a particular value of l shows References glory oscillations and two distinct resonances [1] M. J. Frisch et al. 2016 Gaussian 16 Revision [4]. The origin of these resonances lies in the A.03 trapping of H atom by the C60 barrier [5]. Fig. 1 [2]T.T.Vehvilainen et al. 2011 Phys. Rev. Lett. B shows partial cross section of scattering for 84 085447 [3]J. M. Thijssen, Computational Physics 2012 (Ox- H+Kr@C60 collision for l=0. For case (a), the resonances are observed for ford Univ. Press) energies lying between 0.14 to 0.15 a. u. [4] S. Yu. Ovchinnikov et al. 2006 Phys. Rev. Lett. A 74 042706 Interestingly, these resonances fall on maxima [5] J. Peter Toennies et al. 1979 A. I. P. 71 614 or minima of glory oscillations depending on [6] Wigner P. Eugene 1955 Phys. Rev. Lett. 98 145 even or odd values of l. Consequently, this will determine the shape of the resonances. For case
E-mail: [email protected]
10 ISAMP TC-7, 6 8 January, 2018, Tirupati IA007E Kushawaha − Photoionization of polyatomic molecules: multi-slits type interferences, molecu- lar fragmentation and ultrafast dynamics
R. K. Kushawaha*, 1
* Physical Research Laboratory, Ahmedabad – 380009, Gujarat, India
Topic: A (or E)
In this talk, the core- and inner-valence pho- to picoseconds or longer. Finally, the molecular toionization of molecular systems will be dis- alignment and probing the electronic and nucle- cussed and recent findings on the Young’s dou- ar wave packets by pump-probe scheme [3] will ble-slit type oscillations in cross sections will be be discussed in detail. reported. The signature of beyond the double- slit type oscillation in cross section of butane In PRL, we are developing a femtosecond laser will be presented. A new method for estimating lab for studying the ultrafast processes in the butane and anti-butane conformal equilibria atomic and molecular systems. In talk, I will be will be discussed. explaining the details about planned experiments. Recent finding on isomer-dependent fragmenta- tion dynamics of inner-shell photoionized References Difluoroiodobenzene based on coincidence im- [1] Maria Novella Piancastelli et al., 2014 Journal aging techniques will be covered in this presen- of Physics B: Atomic, Molecular and Optical Phys- tation. In this study, we conclude that the charg- ics, 47, 124031 es on the di- and tri-cation delocalize on an ul- [2] Rajesh Kumar Kushawaha et al., 2013, PNAS., trafast timescale, and in some fragmentation 110 15201-15206. channels of the tri-cation involve step-wise [3] Artem Rudenko et al, 2016, Faraday Discuss., fragmentation with a delay between the two 194, 463-478 steps ranging from a few hundred femtoseconds
1E-mail: [email protected]
11 ISAMP TC-7, 6 8 January, 2018, Tirupati IA008 Natarajan −
Probing quantum effects via X-ray spectroscopy
L.Natarajan
Department of Physics, University of Mumbai, Mumbai-400098
Topic A
In this talk, two extreme cases of atomic case, He-like ions with empty K shell and only configurations and the resulting radiative decay two electrons in the L shell are investigated. In are considered: a) only two electrons knocked principle, the estimated reliable atomic data out and b) only two electrons present. In the should be independent of the choice of the first case, an empty K shell with an otherwise optimization approach, whether one uses relaxed normal atomic configuration (hollow atoms) is or frozen spin orbitals. This gets violated in studied. The structureof the KαX-ray spectrum some unconventional non-resonant transitions from hollow atoms is the onlytesting ground and shows a strong dependence of the estimated to prove LS,intermediate and JJ coupling line intensities of X-ray photons on the nature schemes. The effects of correlation that of orthogonalization of the spin orbitals [3]. The influence the angular momentum coupling calculations are based on Multiconfiguaration scheme will be investigated by analyzing the Dirac-Fock methods with the inclusion of finite resonant and non-resonant transitions to empty nuclear size and higher order corrections [4]. K shell from L subshells [1,2]. In the second
References [1] L.Natarajan 2008 Phys. Rev. A 78 052505 [2] Riddhi Kadrekar and L.Natarajan ,2010 J.Phys. B Atomic ,mol. and Opt.Phy 43 155001 [3] L.Natarajan, , 2014 Phy. Rev.A 90 032509 [4]P.Jonsson etal , 2013 Comp.Phys.Commun 184 2197
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Email: [email protected]
12 ISAMP TC-7, 6 8 January, 2018, Tirupati IA009B Chakraborty − The Fullerene molecule: a super-attractive object for new spectroscopy
Himadri Chakraborty
Department of Natural Sciences, D.L. Hubbard Center for Innovation and Entrepreneurship, Northwest Missouri State University, Maryville, Missouri 64468, USA
Topic: A, B
Empty fullerenes and atom-encaging fullerenes as targets. Straddling the line between endofullerenes are quintessential symmetric atoms and condensed matters, Fullerenes support molecules exhibiting stability in the room tem- quasi-free electron gas within a finite region of perature. This property endows them with the well-defined boundary, as opposed to a longer- quality of being tested for spectroscopic infor- range, highly diffused Coulomb-type boundary mation which are otherwise inaccessible using characteristic of atoms and molecules. This en- regular atoms or molecules. Probing the response sures predominant electron capture from local- of these systems to radiations is one classic way ized regions in space spawning novel resonant to access the dynamics in which the photoelec- diffractions in Ps formation as a function of the tron count as a function of energy predicts varie- recoil momentum [8]. Impacting positrons can ties of resonances. These resonances from the also provide enough energy to excite fullerene plasmonic electron motions [1] or the molecule’s plasmons. Since these plasmon energies are de- structural symmetry inducing diffractions [2] or generate with the molecular ionization continua, the mixing of both these effects in tandem. An a large number of electrons will be resonantly exotic genre of these resonances includes photo- knocked out directly or via the endohedral excitation at one site in the molecule and its sub- atomic emissions and thereby facilitating en- sequent decay at a different location [3], the in- hanced capture rates. ter-Coulombic decay (ICD). A coherent admix- A selection of the results will be presented ing of the ICD mechanism with localized Auger which are computed by the density functional processes is a commonplace outcome [3,4]. method where the fullerene ion-core is jelli- Another contemporary form of spectroscopy umized. The ground state of the molecule has is the determination of the attosecond time-of- been described in a local density approximation flight of the photoelectron from its production- (LDA) framework where a linear-response vari- site in the molecule to the detector. This may uti- ant of LDA, the time-dependent LDA (TDLDA), lize a Wigner clock based on the knowledge of is utilized to describe the interaction with the the energy-dependent quantum phase of bound- field of external stimulus [9]. Results can probe continuum transitions. The Wigner time is abun- versatile territories of research applied to molec- dantly sensitive to the underlying electron correl- ular nanomaterials with novel experimental in- ative dynamics, both at the energy region of the terests. giant plasmon resonance [5] and at generic The research is funded by the US National Cooper [6] and cavity [7] minima anti-reso- Science Foundation. nances. By supporting the coherent and collective References electron motion, fullerenes are great candidates [1] Madjet et al, 2007 Phys. Rev. Lett. 99, 243003 for ion-impact studies as well. If the projectiles [2] McCune et al, 2009 Phys. Rev. A 80, 011201(R) are completely stripped off the bound electrons, [3] De et al, 2016 J. Phys. B Letter 49, 11LT01 their interactions with a fullerene target can un- [4] Javani et al, 2014 Phys. Rev. A 89, 063420 leash pure plasmonic dynamics driven by the ion [5] Barillot et al, 2015 Phys. Rev. A 91, 033413 field. Since the ion impact can render the target’s [6] Dixit et al, 2013 Phys. Rev. Lett. 111, 203003 non-dipole response significant, this method can [7] Magrakvelidze et al, 2015 Phys. Rev. A 91, allow access to strong collective motions in 053407 mono- and quadrupole ionization channels. [8] Hervieux et al, 2017 Phys. Rev. A 95, 020701(R) [9] Choi et al, 2017 Phys. Rev. A 95, 023404 Finally, a brand new spectroscopic direction emerges via the positronium (Ps) formation with
E-mail: [email protected]
13 ISAMP TC-7, 6 8 January, 2018, Tirupati IA010 Sharma − A three-dimensional ion imaging spectrometer for studying photo-induced fragmentation in small molecules
R. Gopal1, A. Sen2, Anbu S. Venkatachalam3, Shilpa R. Sahu3, M. Anand1, V. Sharma3*
1Tata Institute of Fundamental Research, Sy. No 36/P, Gopanpally Village,Hyderabad 500107, India 2Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India 3Department of Physics, Indian Institute of Technology, Hyderabad, 502285, India
Topic: A
We indigenously designed and constructed an ion we can correlate KE spectra obtained in 2D imag- imaging spectrometer [1] to study photo-induced ing mode to KE distributions extracted from time- fragmentation dynamics of molecules using of-flight spectra to calibrate the images. The KE femtosecond laser pulses. The imaging spectrom- distributions along with the angular distributions eter is capable of recording three-dimensional ion allow us to assign pathways to the distribution for momentum and we illustrated capabilities of spec- even a complex molecule such as O2 which is trometer through the momentum spectra of O+ ion emphasized by the capability of distinguishing resulting from fragmentation of O2 in moderately vibrational levels. strong (~1013 W/cm2) femtosecond laser fields. During presentation we also will present a recipe References for self-consistent calibration of kinetic energy [1] André T. J. B. Eppink and David H. Parker, Rev. Sci. (KE) spectra by operating the spectrometer in a Inst, 68, 3477 (1997) non-imaging time-of flight mode. Consequently,
*E-mail: [email protected]
14 ISAMP TC-7, 6 8 January, 2018, Tirupati IA011 Aravind − Collision-induced dissociation of anions of astrophysical interest
G. Aravind* 1 and Roby Chacko* 2
* Department of Physics, IIT Madras, Chennai – 600036, Tamil Nadu, India
Topic: A
Anions have been only recently detected target resulting in collisional excitation to reso- in the interstellar medium (ISM) although E. nance states. From these resonance states, Herbst [1] predicted their presence more than which are short-lived, forms the negatively three decades earlier. Recent identification of charged fragment ions. We have measured the six carbon-containing anions such as kinetic energy distributions of the fragments C6H¯(McCarthy et al. [2], C4H¯(Cernicharo et and deduced the potential energy curves of the al. [3], Gupta et al.[4]), C8H¯(Gupta et al. [4]), resonances in case of the diatomic anions. The and CnN͞͞ ¯ (n= 1,3,5) (Agundez et al. [5]) moti- resonances in CnN¯ show rich dissociation dy- vates the study of their stability and search for namics. We have employed the kinetic energy other carbon containing anions in the astrophys- distributions to identify the dissociation path- ical environment. ways. In this talk we shall discuss the im- Anion resonances are electronic states that portance of our results on resonances in deter- are embedded in the detachment continuum. mining abundances of ISM anions and their sta- They play a vital role in the Astrochemistry. bility. ISM anions could be excited via photon or col- lisional excitation under extreme situations References thereby accessing the resonances. The reso- [1] Herbst, E. 1981, Natur, 289, 656 nances in polyatomic anions are complex poten- [2] McCarthy et al. 2006 ApJ, 652, L141 tial energy surface leading to various dissocia- [3] Cernicharo, J., et al. 2007, A&A, 467, L37 tion pathways. The resonances thus determine [4] Gupta et al. 2007, ApJ, 655, L57 the formation and stability of anions in the ISM. [5] Agundez et al., 2010, A&A, 517, L2 In this talk, we will discuss our experimental [6] Nrisimhamurthy M., et al., 2016, ApJ, 833, results on collision induced dissociation of ISM 269 anions such FeO¯, FeC¯[6], CnN¯. Fast moving ISM anions were made to collide with Argon
1 E-mail: [email protected] 2 E-mail: [email protected]
15 ISAMP TC-7, 6 8 January, 2018, Tirupati IA012 Rao − Quantum symmetry effects and isotopic effects in oxygen exchange reactions
1 T. Rajagopala Rao∗ ,
∗ Department of Chemistry, IIT Patna, Bihta –801103 , Bihar, India
Topic: A
The O + O2 collision is now known to play a References key role in the formation of atmospheric ozone, because it is closely related to the ozone forma- [1] K. Mauersberger 1981 Geophys. Res. Lett. 8, 935- 937 tion, O + O2 + M O3 + M [1,2,3,4,5]. In- → [2] M. H. Thiemens and J. E. Heidenreich III 1983 deed they proceed through the same O3∗ interme- diate complex (excited ozone). An in-depth un- Science 219 1073-1075 derstanding of the bimolecular isotope exchange [3] K. Mauersberger, B. Erbacher, D. Krankowsky, J. reactions will therefore not only advance our Gunther and R. Nickel 1999 Science 283 370-372 knowledge of complex-forming reactions in gen- [4] Y. Q. Gao and R. A. Marcus 2001 Science 293 eral, but also shed light on the mass independent 259-263 fractionation of ozone. [5] R. A. Marcus 2013 Proc. Natl. Acad. Sci. USA 110 17703-17707
We will show the results of an extremely com- [6] R. Dawes, P. Lolur, A. Li, B. Jiang and H. Guo, 2013 J Chem Phys 139 201103 putational intensive full-quantum investigation 16 32 of the dynamics of the O + O2 collision and [7] T. Rajagopala Rao, G. Guillon, S. Mahapatra and its isotopic variants, on a recent accurate global P. Honvault 2015 J. Phys. Chem. Lett. 6 633-636 potential energy surface for the ground state of [8] T. Rajagopala Rao, G. Guillon, S. Mahapatra and ozone [6]. Our study takes into account the indis- P. Honvault 2015 J. Chem. Phys. 142 174311 tinguishability of the three identical atoms and [9] T. Rajagopala Rao, G. Guillon, S. Mahapatra and yield accurate cross sections and rate constants P. Honvault 2015 J. Phys. Chem. A 119 11432- [7,8,9]. 11439
1E-mail: [email protected]
16 ISAMP TC-7, 6 8 January, 2018, Tirupati IA013 Osterwalder − Merging, splitting, orienting – towards ultracold stereodynamics
Sean Gordon, Junwen Zhou, Silvia Tanteri, Nikolaos Gkogkoglou, and Andreas Osterwalder1
Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
Topic: A
Merged neutral beams have enabled the investiga- electroplating. This approach opens many possi- tion of sub-Kelvin chemical reactions in molecular bilities for the generation of scientific appa- beams. In the past years we have conducted several ratus, and it will greatly simplify and accelerate Penning ionization studies of polyatomic molecules, the design, production, testing, and exchange of targeting characteristics that arise from the presence experimental components. We have recently of multiple rotational degrees of freedom and from used this method for the first time by printing the anisotropic shape of such systems are accessi- the beam splitter for neutral polar molecules ble. shown in figure 1.[2] With this device a single Here I will give an overview of our recent ex- supersonic expansion is split, using electrostatic periments,[1] both in crossed and in merged guides, into two nearly identical components. beams, on stereo dynamical aspects where we This permits, for example, differential measure- orient, e.g., the angular momentum of a meta- ments with correlated probe and reference stable rare gas atom prior to reaction. Strong beams. orientation-dependent changes in the branching ratio between different reaction channels permit the determination of state-specific reaction cross sections for levels that differ only by their magnetic quantum number, and to do so in an Figure 1. Photograph of our 3D printed, electroplated energy range from 0.1 K to several 100 K. beam splitter for molecular beams.[2] I will also present a new method to produce References electrically conductive structures for, e.g., high- voltage applications inside high-vacuum: the [1] Phys. Rev. Lett. 119, 053001 (2017). [2] Phys.Rev.Applied 7, 044022(2017). 3D printing of a plastic structure, followed by
1E-mail: [email protected]
17 ISAMP TC-7, 6 8 January, 2018, Tirupati IA014 Fritzsche − Excitation and ionization of atoms by twisted light
1 Stephan Fritzsche∗†
∗ Helmholtz-Institut Jena, 07743 Jena, Germany † Theoretisch-Physikalisches Institut, Universit¨atJena, 07743 Jena, Germany
Topic: A
Optical vortex beams, often referred to as nicely with recent observation [9], in which the twisted light, have attracted much interest dur- excitation of atoms, placed upon the axis of an ing the past 20 years. In particular, the spin incident Laguerre-Gaussian beam, was seen to be and orbital angular momentum distributions of determined by the OAM of the beam. – A similar such vortex beams have been explored theoreti- behaviour has been found also for the scattering cally in good detail. Much less is known however of twisted electrons, although with a quite differ- about their interaction with (clouds of) atoms ent physics behind. and molecules, and how the orbital angular mo- mentum (OAL) of the incident light affects the References photoelectron emission or the subsequent fluo- rescence. In this work, I shall review and dis- [1] A. Surzhykov et al., 2015, Phys. Rev. A 91, cuss recent results from our group on the exci- 013403. tation and ionization of atoms by twisted light [2] O. Matula, A. G. Hayrapetyan, V. G. Serbo, [1,2]. Emphasis will be placed especially on the A. Surzhykov and S. Fritzsche, 2013, J. Phys. B interaction of localized atomic targets and with 46, 205002. (Bessel) beams of various intensity [3–5] [3] A. Surzhykov, D. Seipt and S. Fritzsche, 2016, For weak vortex fields, the excitation of Phys. Rev. A 94, 033420. atoms and ions is described most naturally within the framework of the density matrix the- [4] R. A. M¨uller et al., 2016, Phys. Rev. A 94, 041402(R). ory [6,7]. General expressions were derived for the alignment of the (excited) states as well as [5] B. B¨oning et al., 2017, Phys. Rev. A 96, 043423. the angular distribution of the subsequent flu- [6] V. V. Balashov, A. N. Grum-Grzhimailo and orescence emission, if excited by a Laguerre- N. M. Kabachnik, Polarization and Correlation Gaussian beam, a Bessel beam, or the coherent Phenomena in Atomic Collisions (Kluwer Aca- superposition of several such beams. For these demic/Plenum Publishers, New York, 2000). beams, we have shown that, both, the relative [7] A. A. Peshkov et al., 2016, Phys. Scr. 91, 064001. population of the magnetic substates as well as the angular distribution of the fluorescence radi- [8] A. A. Peshkov, D. Seipt, A. Surzhykov and ation, are sensitive to the transverse momentum S. Fritzsche, 2017, Phys. Rev. A 96, 023407. and the (projection of the) total angular momen- [9] C.T. Schmiegelow et al., 2016 Nat. Commun. 7 tum of the incident radiation [8]. This agrees 12998.
1E-mail: [email protected]
18 ISAMP TC-7, 6 8 January, 2018, Tirupati IA015 Tennyson − Low temperature chemistry using the R-matrix method
Jonathan Tennyson 1
Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
Topic: A
A quiet revolution is occuring at the border tion methods are used to provide wavefunctions between atomic physics and experimental quan- (both bound and continuum) for the whole sys- tum chemistry. Techniques for producing cold tem at short internuclear distances only. These and ultracold molecules are enabling the study collision-energy-independent, inner-region wave- of chemical reactions and heavy-particle scatter- functions are then used to construct collision- ing at the quantum scattering limit with only energy-dependent R-matrices which can then be a few partial waves contributing to the incident propagated to asymptotia. channel leading to the observation and even full Progress on the project will be described in- control of state-to-state collisions in this regime. cluding results of a series of test calculations on We have developed a new R-matrix-based for- various systems including ultra-low energy Ar – malism for tackling problems involving low- and Ar collisions. ultra-low energy collisions between heavy par- ticles [1]. This formalism is completely general References and could prove transformative in its scope. It is particularly appropriate for slow collisions occur- [1] Tennyson J., McKemmish L.K., Rivlin T., 2016, ing over deep potential energy wells which sup- Faraday Discuss, 195, 31. port many bound ro-vibrational states. These [2] Burke P.G., 2011, R-Matrix Theory of Atomic systems support many quasibound or resonance Collisions: Application to Atomic, Molecular and states. These resonances make such systems hard Optical Processes, Springer. to treat theoretically but offer the best prospects [3] Yurchenko S.N., Lodi L., Tennyson J., Stolyarov for novel physics: resonances are being widely A.V., 2016, Computer Phys. Comm, 202, 262. used to control diatomic systems and should pro- vide the route to steering ultracold reactions. [4] Tennyson J. et al., 2004, Computer Phys. Comm, The R-matrix method [2] involves divid- 163, 85. ing space into an inner and outer region. In [5] Yurchenko S.N., Thiel W., Jensen P., 2007, J. our method, the inner region exploits codes Mol. Spectrosc., 245, 126. for performing high-accuracy variational nuclear- [6] Mussa H.Y., Tennyson J., 1998, J. Chem. Phys, motion calculations of molecular spectra which 109, 10885. have bee developed over many years in my group [3,4,5]. The codes have already be used to com- [7] Zobov N.F. et al., 2011, Chem. Phys. Letts, 507, pute wavefunctions up to [6] and above [7] dis- 48. sociation, revealing interesting and unexpected [8] Munro J.J., Ramanlal J., Tennyson J., 2005, New behaviours [7,8]. These variational nuclear mo- J. Phys, 7, 196.
1E-mail: [email protected]
19 ISAMP TC-7, 6 8 January, 2018, Tirupati IA017 Nandi − Dissociative electron attachment and dipolar dissociation dynamics probed by velocity slice imaging
Dhananjay Nandi 1
Department of Physical Sciences, IISER Kolkata, Mohanpur – 741246, West Bengal, India
Topic: A.
Electron collisions with gas phase molecules leading to dissociative electron attachment The dynamics in the DD process has (DEA) and dipolar dissociation (DD) have fun- been explained in the light of direct and in- damental as well as applications in various direct excitation to the ion-pair states that branches of science. DEA is a resonant process eventually dissociate into anion and cation. whereas DD is a non-resonant process, however, the detecting particle(s) is/are anion(s) in both the cases. Moreover, the associated particle af- ter the reaction is a neutral and a cation for DEA and DD process, respectively. We developed a velocity slice imaging tech- nique to study detailed dynamics in the DEA and DD process at IISER Kolkata recently. Few simple molecules have been studied and obtained very interesting results that will be present in the conference. The representative graphs show DEA and DD to carbon monoxide. Detailed dynamical studies on DEA to CO showed that the involvement of two temporary negative ion (TNI) states. Figure 2. Fragmentation dynamics of ion-pair states of carbon monoxide in electron collisions through direct and indirect excitation.
References
[1] P. Nag et al. 2015 Phys. Chem. Chem. Phys. 17 7130 [2] S. X. Tian et al. 2013 Phys. Rev. A 88 012708 [3] K. Gope et al. 2016 Eur. Phys. J. D 70 134 Figure 1. (a) Velocity slice image of O− ion at 11 eV incident electron and (b) angular distribution of [4] D. Chakraborty et al. 2016 Phys. Chem. Chem. Phys. 18 32973 the ions at 11 eV with the fitted curves.
1E-mail: [email protected]
20 ISAMP TC-7, 6 8 January, 2018, Tirupati IA018 Krishnan − Electron dynamics in small atomic aggregates at He nanodroplets: multi- coincidence spectroscopy
Sivarama Krishnan* 1
* Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
Topic: A.
We will present representative results from our investigations of small atomic and molecu- lar clusters attached to He nanodroplets interro- gated by coincident photoelectron-photoion spectroscopy at the Elettra synchrotron. When photoexcited between 20…30eV across the atomic ionization threshold of He, we find intri- guing behaviour of the systems attached to the host He droplets both by Penning transfer of energy from the single-photon excited He ma- trix to the dopant system, as well as by charge- transfer from He to the dopant system when photon energies were sufficient to directly ion- ize the droplet [1, 2]. Using alkali, alkaline earth [3] and rare gas dopant clusters as well as small molecules attached to these droplets, we explore the fascinating dynamics of these com- plex atomic systems.
References 1) D Buchta, S R Krishnan, et al., The Journal of chemical physics 139 (8), 084301 (2013). 2) ibid., The Journal of Physical Chemistry A 117 (21), 4394-4403 (2013) 3) A C LaForge et al., Physical review let- ters 116 (20), 203001.
21 ISAMP TC-7, 6 8 January, 2018, Tirupati IA019 Lopez − Multichannel photoionization of polyatomic non-linear targets within the XCHEM approach: the H2O case study.
1 , Jes´usA. L´opez-Dom´ınguez,† Markus Klinker,† Carlos Marante,† Luca Argenti,† ‡ Jes´us , , 2 Gonz´alez-V´azquez,† Fernando Mart´ın† § ∗
† Departamento de Qu´ımica,M´odulo13, Universidad Aut´onomade Madrid, 28049 Madrid, Spain, EU ‡ Department of Physics and CREOL College of Optics & Photonics, University of Central Florida, Orlando, Florida 32816, USA § Instituto Madrile˜node Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain, EU
∗ Condensed Matter Physics Center (IFIMAC), Universidad Aut´onomade Madrid, Spain, EU
Topic: A.
From a theoretical point of view, the dial region, allows for the use of QCP to de- main challenge when studying ionizing phe- scribe neutral and parent-ion states, and a set nomena, is to obtain an accurate (and not-so- of added and pure B splines over the mid- and computationally expensive) representation of the long-range respectively, permits the accurate de- system’s electronic continua. So far, most com- scription of scattering or photoionization observ- mercially available quantum chemistry packages ables [1]. In the present work, we applied this (QCP) have excelled, to a very reasonable level, method to theoretically study the multichannel 1 in implementing and refining methods to repre- photoionization of H2O, including the (1b1)− , 1 1 sent bound molecular electronic states. With (4a1)− and (2b2)− channels. Looking at the this in mind, efforts in our group to provide total cross sections below the highest ionization a feasible and flexible enough method to de- threshold under consideration, several resonant scribe ionizing electronic continua for a wide features are apparent, which are usually over- range of systems has led to the development looked, and by looking at the cross sections for in- of a Hybrid Gaussian-B-spline basis (GABS) [1] dividual channels and scattering symmetries, we which interfaces QCP, and altogether with close- were able to determine the importance of inter- coupling scattering methods have already proven channel effects too. Although a continued effort successful in treating a variety of ionizing prob- exists on our side to improve current capabilities lems, ranging from the photoionization of atomic of our code, we expect that the results herein [1] and molecular [2] hydrogen to polyelectronic shown, will suffice to convince of the usefulness atoms, He [2] and Ne [3], and even for the di- and potential of the XCHEM code approach to atomic N2 [4]. study such multichannel ionizing processes both Following the aforementioned success in ac- in atoms and molecules, providing the needed counting for the electron correlation in the con- tools to study, among other things, the dynami- tinuum for different ionizing phenomena in poly- cal effects in photoionization. electronic atoms and even diatomic molecules, the subsequent natural pursue has been to try References the feasibility in terms of computational effort and physical accuracy of the method in describ- [1] Marante C, Argenti L and Mart´ınF 2014 Phys. Rev. A 90 102506 ing a polyatomic non-linear molecule, where the reduced symmetry, and thus, added angular de- [2] Marante C, Klinker M, Corral I, Gonz´alez- pendencies play a major role in the correlation V´azquezJ, Argenti L and Mart´ınF 2017 J. Chem. and exchange effects that shapes the continuum Theory Comput. 13 499 in, for example, a photoionization experiment. [3] Marante C, Klinker M, Kjellsson T, Lindroth E, The very nature of the GABS basis contain- Gonz´alez-V´azquezJ, Argenti L and Mart´ınF 2017 ing, a large enough, pure Gaussian representa- Phys. Rev. A 96 022507 tion of the electronic wave function in the ra- [4] To be published.
1E-mail: [email protected] 2E-mail: [email protected]
22 ISAMP TC-7, 6 8 January, 2018, Tirupati IA020 Tribedi − Angular asymmetry of electron emission and ionization dynamics
Lokesh C Tribedi 1
Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India
Topic: A
Ejected electron double differential distribu- chanical Cohen-Fano interference effect in a tions in collisions with atoms and molecules molecular double-slit. The latest advances in carry the signature of different features of colli- some of these features using electrons, photons sion dynamics [1-15]. The angular distributions and ions will be emphasized will be presented. for simple atoms can be described by some of the Coulomb ionization models, such as, con- References tinuum distorted wave approximation etc. In [1] S. Biswas et al. 2015 Phys Rev A 92, 060701 (R) addition, the derived quantity such as forward [2] A. Kelkar et al, 2015 Phys Rev A 92 052708 backward asymmetry which is to some extent [3] S. Bhattacharjee et al, 2016 J Phys B 49 065202 termed as angular anisotropy has been shown to [4] A. Agnihotri et al, 2013 Phys Rev A 87 032716 be sensitive to the collisional features, such as, [5] A. Agnihotri et al, 2012 Phys Rev A 85, 032711 binary nature, post-collisional two center- [6] S. Kasthurirangan et al, 2013 PRL 111, 243201 interaction, in atoms and small molecules in- [7] U Kadhane et al. 2003 PRL 90, 093401 cluding water, Young type electron interference [8] D. Misra et al. 2004 Phys Rev Letts. 92 153201 in case of di-atomic molecules, collective exci- [9] D. Misra et al 2005, Phys. Rev Letts 95, 079302 tation in case of mesoscopic objects, fullerenes [10] Ilchen et al.2014 Phys. Rev. Letts 112, 023001 or PAH-molecules, or size-effect in case of [11] M. Roy Chowdhury et al 2016 PRA 94 052703 DNA/RNA -bases The collision physics involv- [12] M. Roy Chowdhury et al 2017 JPB 55, 155201 ing large molecules is closely related to inter- [13] M. Roy Chowdhuri et al 2017, EPJ D71, 218 disciplinary science whereas that involving [14] S. Bhattacharjee et al 2017 Euro P J D (in press) smallest di-atomic molecules, e.g. H2, N2 or O2 [15] S. Bhattacharjee et al, 2017 PRA 96, 052707 closely deals with fundamental quantum me-
1 E-mail: [email protected]
23 ISAMP TC-7, 6 8 January, 2018, Tirupati IA021 AzumaY − Post Collision Interaction (PCI) Recapture of Photoelectrons in- to Rydberg Orbitals: Electrons Playing Tag at Threshold
Yoshiro Azuma
* Faculty of Materials and Life Sciences, Sophia University, Chiyoda-Ku, Tokyo, JAPAN 102-8554
Topic: A
Inner-shell photoionization and photo- Region 3. excitation of atoms can be followed by further As the photon energy is made even lower, ejection of electrons due to Auger effects. The going below threshold, the process will turn into interaction of photoelectrons and Auger elec- the resonant Auger process, i.e.photoexcitation trons upon this process, the Post Collision Inter- followed by a spectator Auger process which action (PCI) effects can provide fertile ground can induce shakeup and or shakedown of the for research on multi-electron dynamics involv- photoexcited electron. ing multi-electron effects involving the continua. The PCI effect is particularly prominent in the It is important to note that the above four photon energy region close to the photoioniza- regions, distinct as they are in terms of physical tion threshold. It is interesting to trace the com- processes, nevertheless connect seamlessly ing and going of PCI effects in various forms as from one to another as the photon energy is var- one varies the photon energy from way above ied continuously. the photoionization threshold to well below. We find it useful to define four photon energy re- The current status of research in each of gions from above to below the photoionization the above regions will be reviewed. In particu- threshold as follows. lar, new results on the photoelectron recapture processes in region 2 show unexpected effects Region 0: due to dynamic correlation. Most of the previ- Way above photoionization threshold ous research explained PCI processes in terms where the photoelectron is much faster than the of radial correlation between the photo- and Auger electrons. There is little chance for inter- Auger electron. Nevertheless, our results on Kr action between the photoelectron and the Auger 3d photoionization is dominated by prominent electron. The Auger electron peak exhibits the conjugate processes due to the exchange of an- Lorenzian line-shape manifesting the Auger gular momentum. For Xe 4d photionization, lifetime width. Angular distributions of the Auger electrons were measured, and variation of the patterns Region 1: were found not only depending on the angular Post Collision Interaction (PCI) effects ap- momentum state of the recaptured electron, but pear as the shift and continuous tailing of the the angular momentum state dependence itself photoelectron peak toward lower energy as well depended on the principal quantum number. as the shift and tailing of the Auger electron peaks toward higher energy. In recent years, quantum entanglement has been found to be more and more ubiquitous in Region 2: various atomic processes. Nevertheless, some Then, as the photon energy is tuned lower, unique type of manifestations in the photoelec- very close above the threshold, photoelectrons tron recapture processes are worth pointing out. may return back and get recaptured into one of the Rydberg orbitals of the final ionic state. Due References to energy conservation, this process manifests [1] H. Aksela, M. Kivilompolo, E. Nommiste and S. as the Rydberg series structure of the ionic final Aksela, Phys. Rev. Lett. 79, 4970 (1997). state imprinted exactly as narrow fine structures [2] S. Kosugi, M. Iizawa, Y. Kawarai, Y. Kuriyama, in the wide Auger electron peak. A.L.D. Kilcoyne, F. Koike, N. Kuze, D.S. Slaughter and Y. Azuma, J. Phys. B 48, 115003 (2015).
E-mail: [email protected]
24 ISAMP TC-7, 6 8 January, 2018, Tirupati IA022 Champion − Dosimetry of ionizing radiations in biological tissues: Importance of calculations at a microscopic scale Champion Christophe* 1
* Centre Lasers Intenses et Applications, Université de Bordeaux, Bordeaux, France
Topic: A.
When biological matter is irradiated by A detailed overview of the code will be ex- charged particles, a wide variety of interactions posed along this talk with in particular its relat- occur, which leads to a deep modification of the ed version - called CELLDOSE - devoted to cellular environment. To understand the fine absorbed dose calculation in nanometer-size structure of the microscopic distribution of en- volumes for radio-isotopes of medical interest ergy deposits, the Monte Carlo event-by-event [7-8] providing accurate quantities such as dose simulations are particularly suitable. However, point kernel (DPK) functions and S-values that the development of these track structure codes are commonly used in radiopharmaceutical do- requires a large set of accurate multiple differ- simetry (see Figure). ential and total cross sections for describing all the collision processes including the ionization, the electronic excitation, the elastic scattering and the Positronium (Ps) formation event when incident positrons are considered. In this context, we have recently developed a Monte Carlo code for electron and positron tracking in water. All the processes are studied in detail via theoretical differential and total cross section calculations performed within the quantum mechanical framework. Comparisons with existing theoretical and experimental data in terms of stopping powers, mean energy trans- fers and ranges have shown a very good agree- ment. Moreover, thanks to the theoretical de- scription of Ps formation, we access to the complete kinematics of the electron capture Figure 1. Dose profile (S-value) within concentric process [1-2]. Then, the current Monte Carlo shells of 10-µm thickness. code is able to describe the detailed Ps history, what provides useful information for medical References imaging (like Positron Emission Tomography) where improvements are needed to define with [1] Champion C et al. Phys. Med. Biol. 51 1707 (2006). the best accuracy the tumor volumes [3-4]. [2] Champion C et al. Phys. Med. Biol. 52 6605 Besides, recent quantum mechanical models (2007). for treating the electron-induced ionization pro- [3] Champion C et al. J. Nucl. Med. 49 151 (2008). cess in a realistic biological medium have been [4] Zanotti-Fregonara P et al. J. Nucl. Med. 49 679 implemented into the code in order to extend its (2008). applications. Thus, an accurate description of [5] Champion C et al. Int. J. Radiat. Biol. 88 No.1-2 biological volumes of interest - including the 62 (2012). nucleobases as well as the sugar phosphate [6] Champion C J. Chem. Phys. 138 184306 (2013). backbone - may be considered in the current [7] Champion C et al. J. Nucl. Med. 49 151-157 version [5,6]. (2008). [8] Zanotti-Fregonara P et al. Health Phys. 97(1) 82- 85 (2009).
1 e-mail: [email protected]
25 ISAMP TC-7, 6 8 January, 2018, Tirupati IA023 Yugal − Spectroscopic studies and quantum chemical investigations of (3, 4 dimethoxybenzylidene) propanedinitrile − 1 Yugal Khajuria∗
∗ School of Physics, Shri Mata Vaishno Devi University, Kakryal, Katra 182320, Jammu & Kashmir, India −
Topic: A
The Fourier Transform Infrared (FTIR), ergy distribution analysis (VEDA) program. UV- Ultra-Violet Visible (UV-Vis) spectroscopy and Visible spectrum was recorded in the spectral range Thermogravimetric (TG) analysis of (3, 4- of 190-800 nm and the results are compared with the dimethoxybenzylidene) propanedinitrile have been calculated values using TD-DFT approach. Stability carried out and investigated using quantum chemi- of the molecule arising from hyperconjugative in- cal calculations. The molecular geometry, harmonic teractions, charge delocalization have been analyzed vibrational frequencies, Mulliken charges, natural using natural bond orbital (NBO) analysis. The re- atomic charges and thermodynamic properties in the sults obtained from the studies of Highest Occupied ground state have been investigated by using Hartree Molecular Orbital (HOMO) and Lowest Unoccu- Fock Theory (HF) and Density Functional Theory pied Molecular Orbital (LUMO) are used to calcu- (DFT) using B3LYP functional with 6-311G(d,p) late molecular parameters like ionization potential, basis set. Both HF and DFT methods yield good electron affinity, global hardness, electron chemical agreement with the experimental data. Vibrational potential and global electrophilicity. modes are assigned with the help of Vibrational en-
1E-mail: [email protected]
26 ISAMP TC-7, 6 8 January, 2018, Tirupati IA024 Krishnamurthy − Acceleration of neutral atoms in laser produced plasmas
M. Krishnamurthy1
Tata Institute of Fundamental research. Homi Bhabha Road, Mumbai - 400 005 TIFR center for inter-disciplinary sciences, Narasinghi, Hyderabad - 500 107
Topic: A.
Intense laser pulse focused on solid sub- ser focal waist provides an optimal control of strate are well known to generate high density the pre-plasma and can be tuned to alter the high temperature plasma. Electron and ion neutralisation efficiency. emission to a few MeV with laser intensities close to the relativistic intensities are well stud- Generating and analysing a beam of high en- ied. The question we ask is about the possibility ergy neutral atoms is a challenge that is im- of tuning the compact charge particle accelera- portant for many technological application. In tion schemes to generate neutral atoms beam of lithographic applications, high energy neutral the energy same as that of ions As intense laser- atoms result in higher finesse structures than produced plasmas have been demonstrated to those produced with charged particle beams. produce high-brightness-low-emittance beams, High energy hydrogen atom beams play an im- it is therefore possible to envisage generation of portant role in Tokamak diagnostics. A 15 de- high-flux, low-emittance, high energy neutral gree conical emission of neutral atoms with en- atom beams in length scales of less than a mil- ergy as large as MeV is likely impact the possi- limeter. Feasibility of such a high energy neu- ble neutral atom beam applications. tral atom accelerator could significantly impact applications in neutral atom lithography and References diagnostics. We demonstrate [1] in this talk that [1] Compact acceleration of energetic neutral atoms it is possible to device a scheme where in nearly using high intensity laser-solid interaction, Malay 80% of the accelerated ions of heavy atoms like Dalui, T. Madhu Trivikram, James Colgan, John Cu generated at the target front can be reduced Pasley, and M. Krishnamurthy Sci. Rep. (2017) to neutral atoms. We find that adjusting the la-
1 E-mail: [email protected]
27 ISAMP TC-7, 6 8 January, 2018, Tirupati IA025E Subramanian − LTE condition validation by plume characterization in laser produced plasmas
K P Subramanian* 1, B G Patel†, and Prashant Kumar*
* Physical Research Laboratory, Ahmedabad – 380009, Gujarat, India † Institute for Plasma Research, Bhat, Gandhinagar – 382428, Gujarat, India
Topic: E & A
The laser produced plasmas (LPP) are exten- sively been studied for past many decades, and its application ranges from realization of table- top accelerators to fabrication of thin films, nano-tubes etc. Another area which has received a lot of contribution from LPP studies is the la- ser induced breakdown spectroscopy (LIBS). LIBS is now emerging as an important diagnos- tic tool for the quantitative estimation of ele- mental concentrations in a sample. In LIBS, the line emissions from the LPP are analyzed to identify the elements present in a sample as well as their concentration fraction. In the LIBS technique, the existence of LTE is the essential requisite for the application of
Boltzmann and Saha equations that relate fundamental plasma parameters and Figure 1. Shock wave to drag model change-over concentration of sample species. The most exhibited by Al, Cu and Pb LPP plumes. Black curve is the distance of the plume front from the target and popular criterion reported in the literature red curve is the time when the change-over happens. dealing with plasma diagnostics, and usually invoked as a proof of the existence of LTE in Further, studies are conducted to investigate the the plasma, is the McWhirter criterion [1]. Ac- transition of the evolving plume from the descrip- cording to this criterion, the collisional depopu- tion of shock wave to drag model. It is found that lation rates for all electronic levels of the atom the length of the evolved plume boundary (from are to be at least ten times larger than the radia- target) and time (measured from the laser firing) at tive depopulation rate. In this way, it could be which the plume-model switch-over is happening, established that collisional processes prevail are dependent on the atomic mass of the evolving over radiative processes and deviations from plasma species (see Figure 1). This gives us a clue LTE are negligible. that the 'delay' and 'gate' used in LIBS experiment Plume homogenization by the way of ambi- may be dependent of the atomic mass of the sample. ent gas mixing give certain vital information Details of the studies will be presented in the regarding the LTE validity regime. In an exper- conference. iment, the LPP and laser blow-off (LBO) plume evolutions are studied in detail. Attempts are References made to check the validity of invoking the Ray- leigh-Taylor instability for the rupture of evolv- [1] R.W.P. McWhirter, in: "Plasma Diagnostic ing plume boundary in an ambient gas [2]. Techniques", (Eds. R.H. Huddlestone, S.L. Leonard) 1965 Academic Press, New York 201–64. [2] Ajai Kumar et. al 2006 J. Phys. D: Appl. Phys. 39 4860–66 . 1 E-mail: [email protected]
28 ISAMP TC-7, 6 8 January, 2018, Tirupati IB001 Ciappina − Attosecond Physics at the Nanoscale
1 M. F. Ciappina∗
∗ Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, 182 21 Prague, Czech Republic
Topic: B
Recently two emerging areas of research, at- attosecond physics has reached, together with tosecond and nanoscale physics, have started the tremendous advance in material engineering to come together. Attosecond physics deals and manipulation techniques, the age of atto- with phenomena occurring when ultrashort laser nano physics has begun, but it is in the initial pulses, with duration on the femto- and sub- stage. We present thus some of the open ques- femtosecond time scales, interact with atoms, tions, challenges and prospects for experimental molecules or solids. The laser-induced electron confirmation of theoretical predictions, as well as dynamics occurs natively on a timescale down to experiments aimed at characterizing the induced a few hundred or even tens of attoseconds (1 at- fields and the unique electron dynamics initiated 18 tosecond = 1 as = 10− s), which is comparable by them with high temporal and spatial resolu- with the optical field. For comparison, the revo- tion [1]. lution of an electron on a 1s orbital of a hydrogen atom is 152 as. (a) ∼ interaction region On the other hand, the second branch in- [µm] Detector volves the manipulation and engineering of meso- e– scopic systems, such as solids, metals and di- electrics, with nanometric precision. Although xuv nano-engineering is a vast and well-established input pulse 10 13 —1014 W/m 2 gas jet research field on its own, the merger with intense Detector laser physics is relatively recent. We present in this talk a comprehensive ex- perimental and theoretical overview of physics (b) enhanced laser Detector that takes place when short and intense laser field pulses interact with nanosystems, such as metal- e– lic and dielectric nanostructures. In particular xuv Detector we elucidate how the spatially inhomogeneous input pulse gas atoms laser induced fields at a nanometer scale modify 10 10 —1011 W/m 2 interaction region the laser-driven electron dynamics (see Fig. 1 for [nm] a sketch of conventional and plasmonic-enhanced strong field processes). metal nanostructure Consequently, this field characteristic has im- Figure 1. Sketch of conventional (a) and portant impact on pivotal processes such as plasmonic-enhanced (b) strong field processes. above-threshold ionization (ATI) and high-order harmonic generation (HHG). The deep under- standing of the coupled dynamics between these References spatially inhomogeneous fields and matter config- ures a promising way to new avenues of research [1] M. F. Ciappina et al. 2017 Rep. Prog. Phys. 80, and applications. Thanks to the maturity that 054401
1E-mail: [email protected]
29 ISAMP TC-7, 6 8 January, 2018, Tirupati IB002 Varma −
Wigner photoionization time delay studies of the neon 2s → np autoionization resonances
Hari R. Varma
School of Basic Sciences, IIT Mandi, Mandi –175005, Himachal Pradesh, India
Topic: B
Recent developments in attosecond science nance region (~pico seconds) is several order have enabled study of electron correlation in higher compared to the non-resonance region the time domain. A deeper understanding of (~atto seconds). It is further found that, the min- electron correlation and relativistic interactions imal correlation required to produce the nega- can be extracted from the time delay studies[1]. tive time delay is the presence of at least two Time-delay associated with the photoionization continuum channels. The flip in the sign of dynamics is directly related to the energy deriv- time delay disappears when the calculations are ative of the phase of the transition matrix ele- performed at a 3 channel level where only one ment. Hence significant modulation in time de- continuum channel 2p3/2 → εd5/2 is present. The lay is expected in regions where phase varies contrast in the behavior of time delay profile in rapidly (e.g. Cooper minimum, autoionization 7channel and 3 channel calculations indicate the resonances, shape resonances and confinement importance of including all of the relevant chan- resonances etc ). Many of the previous work nels in dealing with the resonance region. have reported time delay studies in the region of Cooper minimum while studies in the region of autoionization resonances are scanty[2, 3].
The present study report the intrinsic Wigner- Eisenbud-Smith time delay in the 2s → np au- toionization resonance region of atomic Neon. Here we report the results using an ingenious combination of relativistic random phase ap- proximation (RRPA) and relativistic multichan- nel quantum defect theory(RMQDT). The cal- culations are performed at two different levels of truncation of the RRPA which enable an ex- amination of the role of various ionization/exci- tation channels in the dynamics. Following trun- Figure 1. Phase shift and time delay for the 7ch cation levels are employed: calculation for Ne 2s → 3p resonance region
(i) 7 relativistic channels from 2p and 2s: 2p An attempt is made to suggest an empirical for- 3/2 mula for time delay in resonance region using → εd5/2, εd3/2, εs1/2; 2p1/2 → εd3/2, εs1/2; 2s1/2 → kp , kp ; the powerful Fano parametrisation techniques . 3/2 1/2 The result obtained using Fano analysis is also (ii) 3 relativistic channels from 2p and 2s: 2p3/2 → εd ; 2s → kp , kp ; shown in the figure (red curve) which nearly re- 5/2 1/2 3/2 1/2 produce the qualitative and quantitative aspects In Figure 1 shown the time delay obtained of the RRPA+RMQDT curve. The results ob- across the 2s → 3p autoionization resonance re- tained for the higher members of resonat series gion using RRPA and RMQDT with 7 channel and its detailed analysis will also be presented. calculation. It shows that photoionization time delay across the resonance region takes both References [1] Pazourek et al. 2015. Rev. Mod. Phy. 87, 765 positive and negative values; initially positive [2] Saha et al. 2014, Phys. Rev. A 90 053406 and then changes to negative. It is to be noted [3] Gruson et al. 2016, Science 354 734 that the magnitude of time delay in the reso- E-mail: [email protected] 30 ISAMP TC-7, 6 8 January, 2018, Tirupati IB004 Lucchese − Aspects of single-photon ionization of molecules with implications for Wigner time delay and high-harmonic generation
Robert Lucchese* 1
* Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
Topic: B. Wigner time delay in collisions and photoionization
The relative phases of photoionization ma- trix elements contributing to the same process 2 are important in determining a number of as- pects of the photoionization process. In molec- ular photoionization, the relative phases of dif- 0 ferent partial waves contributing to the same 0° 15° ionization process determine the molecular- 30° frame photoelectron angular distributions 45° -2 60° (MFPADs). The energy dependence of such 75° phases can be related to the Wigner time delay. 90° General features of the molecular photoioni- -4 zation and their effects on the phase will be giv- PhaseMatrixElementof en, including shape-resonances, autoionization resonances, and geometry dependence of the matrix elements. Additionally, the effects of -6 correlation and the strong energy dependence of 20 40 60 80 100 the Coulomb phase will be discussed. Photon Energy (eV) In Fig. 1 we see the effects of a shape reso- 4 nance on the phase and magnitude of the pho- toionization matrix of N2 for ionization form the 3σg orbital. These matrix elements have been 0° 3 15° used to interpret measured group delays in the 30° 45° photoionization of N2. [1]. 60° Beyond single-photon ionization, the dipole 75° '90° matrix elements in photoionization can be used 2 to understand strong field processes. In particu- lar high-harmonic generation (HHG) can be modeled using the quantitative rescattering (QRS) model, in which one essential element is 1
the matrix elements for photo-recombination of MagnitudeMatrixElementof an electron scattering from a molecular ion. The photo-recombination elements can be 0 computed using the same computational tools as 20 40 60 80 100 are used to compute photoionization matrix el- Photon Energy (eV) ements. In particular, the photorecombina- Figure 1. Phase and magnitude of photoionization ma- tion matrix elements can be obtained from pho- trix elements for N2 in the direction of the polarization of toionization matrix elements by time reversal. the ionizing radiation. Thus features found in photoionization, will al- so affect high-harmonic yields. References A discussion of shape resonances and inter- [1] Schoun S B, Camper A, Salières P, Lucchese R channel coupling in the high-harmonic genera- R, Agostini P and DiMauro L F 2017 Phys. Rev. tion by SF6 [2] will be discussed where the three Lett. 118 033201 highest occupied orbitals all contribute to the [2] Wilson B P, Fulfer K D, Mondal S, Ren X, Tross HHG signal. J, Poliakoff E D, et al 2016 J. Chem. Phys. 145 224305
1 E-mail: [email protected] 31 ISAMP TC-7, 6 8 January, 2018, Tirupati IB005 Dixit − Control of helicity of high-harmonic radiation using bichromatic circularly po- larized laser fields
Gopal Dixit* 1, Álvaro Jiménez-Galán†, Lukas Medišauskas#, and Misha Ivanov†
* Department of Physics, Indian Institute of Technology Bombay Mumbai 400076 India † Max-Born-Institute, Max-Born Strasse 2A, 12489 Berlin, Germany # Max-Planck Institute for the Physics of Complex Systems, Noethnitzer Strase 38, 01187 Dresden, Germany
Topic: B. Wigner time-delay in collisions and photoionization
High harmonic generation in two-color (ω-2ω) counter-rotating circularly polarized laser fields opens the path to generate isolated attosecond puls- es and attosecond pulse trains with controlled ellip- ticity. Microscopically, to achieve high ellipticity, it is advantageous to generate the harmonics from atoms with p-type ground state over s-type ground state. Indeed, for the s-type state successive har- monics have equal amplitude but opposite helicity, yielding isolated attosecond pulses and attosecond pulse trains with linear polarisation, rotated by 120 degree from pulse to pulse. In this work, we suggest a solution to over- come the limitation associated with the s-type ground state. It is based on modifying the three propensity rules associated with the three steps of the harmonic generation process: ionization, propagation, and recombination. We control the first step by seeding high harmonic generation with XUV light tuned below the ionization threshold, which populates bound states that co- rotate with the ω-field. We control the propagation step by increasing the intensity of the ω-field relative to the 2ω-field, further enhancing the chance of the ω-field being absorbed versus the 2ω-field, thus favoring the emission co-rotating with the seed and the ω-fields. If, on the other had, we seed with the radiation that co-rotates with the 2ω-field, we have a conflict between the ionization and the propagation steps, decreasing the contrast in the intensity of successive high harmonics. We demonstrate our proposed control scheme using Helium atom as a target and solving time- dependent Schroedinger equation in two and three-dimensions.
1 E-mail: [email protected] 32 ISAMP TC-7, 6 8 January, 2018, Tirupati IC001 Angom − Quantum Hall states in optical lattices
1 2 3 4 Rukmani Bai∗† , Soumik Bandopadhyay∗† , Sukla Pal∗ , Kuldeep Suthar∗ , Dilip 5 Angom∗ ,
∗ Physical Research Laboratory, Ahmedabad-38009, India, † Indian Institute of Technology, Palaj, Gandhinagar-382355, India
Topic: C
The observation of quantum Hall states in experiments with optical lattices are performed Bose-Einstein condensates is close to experimen- with a background confining potential. So, it is tal realization with the recent developments of in- essential to incorporate it in the theoretical de- troducing synthetic magnetic field in optical lat- scriptions of the experimental results, or to study tices. In this work we examine the quantum Hall the expected signatures of quantum Hall states states in parameter domains close to the Mott in optical lattices. In our studies we have con- lobes and between the Mott lobes. Earlier works sidered a harmonic confining potential, and our have focused on the quantum Hall states in opti- results show what are the expected signatures of cal lattices and close to the Mott lobes. However, quantum Hall states in these systems.
1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 4E-mail: [email protected] 5E-mail: [email protected]
33 ISAMP TC-7, 6 8 January, 2018, Tirupati IC002 Roy − Long Time Evaluation of Bose-Einstein Condensate in a Toroidal Trap
Jayanta Bera1 † and Utpal Roy1 *
1 Indian Institute of Technology of Patna, Bihta, Patna, Bihar- 801103
Topic: C
In recent times, experimental observations of vari- ous novel phenomena in the system of Bose- Einstein condensate (BEC) with long coherence time have established it as one of the most appro- priate candidates to observe and apply towards quantum technology. Theoretical developments, although nontrivial due to the nonlinear nature of the dynamical equation, are of huge importance to understand the physics of formation and dynamics Two condensates start merging (t = 5.85) after of the system in a transparent manner. There have Figure 1: evolving from the initial positions at two diagonally op- been continuous emphasizes to the applications of posite points. BEC towards quantum optics, quantum informa- tion, weak measurement, higher harmonic genera- tion, frustrated optical lattices etc. The dynamical equation for this quantum system, namely, Gross- Pitäevskii equation (GPE), is widely used for weak interatomic interactions. Incorporating various ex- ternal confinements, further makes the dynamics richer and tunable to achieve coherent control. In this work, we consider two condensates formed in the opposite corners of a toroidal trap. Our ap- proach is to solve the corresponding dynamical eq- uation, numerically. Ultraclod atoms in a ring Figure 2: Autocorrelation function for longer evolution time where t = 187.3 is the revival time. shaped trap is already been observed [1]. Two con-
densates at diametrically opposite points of a to- The autocorrelation function is investigated for the roidal potential radially expand along their curva- whole revival time period [fig. (2)]. It is apparent ture. After certain time during their course of ex- that the peaks at regular intervals are clear signa- pansion, the clockwise and anti-clockwise probabil- tures of nonlinearity in the energy spectrum. The ities start merging each other, bringing out quantum formation of the regular peaks are similar to the interference structures [fig. (1)]. Similar interfe- pure quantum system, where a wave packet is visu- rences due to expended condensate is also studied alized as a combination of several eigen states and for some situations [2]. the dynamics is governed by nonlinear enery spec- trum. However, ultracold atomic cloud is a many Explanation of the dynamics and splitting of the body system modeled by an order parameter, where consensate into several parts becomes possible us- understanding long time evolution of a condensate ing the theory of superposition, only till the two becomes quite nontrivial and our analysis paves the components get completely mixedup. However, it way to reveal the same. becomes quite nontrivial to understand the splitting in a later time. It is observed that the dynamics re- References: peat after a certain time, which is designated as re- vival time (Trev). We have also studied the auto- [1] S. gupta et al., (2005), Phys. Rev. Lett,. 95, 143201; W. Rooijakk- ers, (2004), Appl. Phys. B: Laser Opt. 78, 719; L. Amico et al., (2005), correlation function and the corresponding position Phys. Rev. Lett., 95, 063201. space 2D probability densities at various important [2] T. A. Bell et al., (2016), New J. Phys., 18, 035003. time intervals. The nonlinear nature of the system starts contributing and the dynamics shows revival * E-mail: [email protected] and fractional revivals. † E-mail: [email protected]
34 ISAMP TC-7, 6 8 January, 2018, Tirupati IC003D Mukherjee − Precision measurements with trapped ions
Manas Mukherjee*12, Dahyun Yum1 and Tarun Dutta1
1 Department of Physics, NUS, Singapore – 117551, Singapore 2 Centre for Quantum Technologies, Science drive 2, NUS, Singapore – 117543, Singapore
Topic: C D
Trapped and laser cooled barium ion is a system of choice for atomic weak interaction studies. The presence of large number of neu- tron and protons provides an amplification of parity mixing of the electronic states due to electro-weak interaction. Based on the original proposal of N. Fortson to measure the atomic parity violation (APV), we have developed a method of enhancing the effect by using corre- lated atomic states using an entangled pair of ions. However from the experimental point of view the APV measurement still needs some precursor measurements to be performed. One of them is to measure the involved dipole ma- trix elements with a precision comparable to the seminal Cs experiment [1]. Figure 1. The measured values of transition proba- bilities as well as the theoretical values calculated by We have developed and measured the most sig- different groups are shown. The references are as in nificant matrix elements in barium ion with a [1]. precision surpassing the cesium results for the same matrix elements. As observed in figure 1, our measured values for the transition probabili- ties clearly differentiate between the theory val- In this talk, the experimental setup will be dis- ues. This allows different theoretical results to cussed in details along with the recent results benchmark against experiment with a precision and some outlook for the ongoing or future ex- well below one percent. This work is based on periments. the development of a barium ion qubit setup which is also used for quantum information processing. References [1] T. Dutta et al. 2016 Sci. Rep. 6, 29772
* E-mail: [email protected]
35 ISAMP TC-7, 6 8 January, 2018, Tirupati ID001 Rangwala − Atoms, molecules and ions in cavities
Rahul Sawant, Sourav Dutta, Tridib Ray, S. Jyothi, Arijit Sharma and S. A. Rangwala* 1
* Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080, Karnataka, India
Topic: D
The coupling between light and matter can be probing. A more effective way is to construct a manipulated over a range from the very weak to dark MOT. Such a MOT has all the trapped at- the very strong. In quantum optics such a range oms optically pumped into a specific atomic of atom-light coupling is engineered at low light ground state. The trapped atoms can then be intensities. This is done in part by tuning the continuously probed and VRS can be observed light on atomic resonance or slightly detuning it once again [2]. This VRS can now be used as a with respect to the appropriate atomic reso- means to non-destructively detect ions co- nance. Further enhancement of atom-light cou- trapped with the cold atoms. The ions by virtue pling is enabled by interacting station- of being more energetic than the atoms will de- ary/trapped atoms with a single mode of light, plete the atoms and affect the collective strong in a Fabry-Perot cavity. In such experiments, coupling of the atoms to the cavity. The meas- which allow very precise control, multiple as- ure of the atom depletion is directly related to pects of atom-light interactions can be investi- the ion-atom collision rate and this allows the gated. determination of the density of the trapped ions It is then tempting to ask how far we can push in the cavity mode [3]. the cavity coupled systems in order to tease the The challenge of detecting complex multi-level answer to experimentally difficult questions. atoms and molecules is then taken up. In our We present several instances in which a cavity previous experiment [1] this was not possible can be used to measure elusive properties of without repopulating the cavity coupled ground light coupled with atoms, ions, molecules and state, This deficiency can be overcome by a interactions between them. Specifically we are suitable choice of cavity and system parameters, interested in the non-destructive measurements which should allow the measurement of a VRS of interactions between cavity coupled atoms signal for complex atoms and molecules so that and cotrapped ions/molecules and the non- the range of the cavity coupled system as a ge- destructive detection of state selected mole- neric measurement tool is greatly extended [4]. cules. Finally we examine what happens when bright For our experimental system, by construction atoms are coupled to the cavity. In such a case, we cannot put a single atom in collective strong as the cavity length is scanned, for each spatial coupling with a cavity mode. Instead what we mode, two spectrally proximate peaks are ob- routinely do is attain collective strong coupling served. It is then found that one of these two of laser cooled atoms with the FP cavity. In peaks is a laser and the mechanism for this is such a system we see vacuum Rabi splitting of discussed. In such a system the population of externally scanned probe light through the cavi- the system does not invert [5]. ty, when probing on a closed transition. When the coupling is probed in an open transition, the References VRS disappears as the atoms are optically [1] T. Ray, A. Sharma, S. Jyothi, and S. A. Rangwala, Phys. pumped out of the cavity coupled transition [1]. Rev. A 87, 033832 (2013). This is a serious problem when one wants to [2] S Dutta, SA Rangwala, Applied Physics Letters 110 (12), 121107 probe a multiple level molecule using the same [3] S Dutta, SA Rangwala, Physical Review A 94 (5), 053841 technique. [4] Rahul Sawant, Olivier Dulieu and SA Rangwala, In the above experiment the atoms were optical- Under preparation ly pumped into a particular ground state before [5] Rahul Sawant, SA Rangwala. Scientific Reports 7, probing, and then released from the trap while Article number: 11432 (2017)
1.E-mail: [email protected]
36 ISAMP TC-7, 6 8 January, 2018, Tirupati ID002 Sudhir − Quantum measurement and control of a mechanical oscillator
1 V. Sudhir∗ , D. Wilson, S. Fedorov, H. Schutz, R. Schilling, T. J. Kippenberg†
∗ LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, USA † Institute of Physics, Ecole Polytechnique Federale de Lausanne, Switzerland
Topic: D. Trapping and manipulation of quantum systems
Over the past decade, it has become possi- dergoing random changes, the state of the mea- ble to measure and control solid-state mechan- suring instrument also undergoes changes. In our ical oscillators with a precision that allows to experiment, we observe this as a change in the witness their zero-point motion. This advance state of the light used to measure the motion has been predicated by the ability to tightly in- of the string: the coherent state of the laser is tegrate nano-scale mechanical oscillators with transmuted into a non-classical squeezed state af- high-finesse optical micro-cavities, so that the ter the measurement. We use feedback to study motion of the oscillator can be interferometri- various manifestations of this property, including cally measured. In our group at EPFL, we have a direct measurement of the magnitude of the pioneered some of these advances, and have used position-momentum commutation relation [3]. the technology to investigate the predictions of Finally, we demonstrate that the same phe- quantum theory on a macroscopic object [1]. nomena can be observed when the oscillator is at room-temperature. In this case, we are able We couple the motion of a glass nanostring to to observe the effect of the quantum correlations the frequency of a high-finesse whispering-gallery developed in the light field due to its interaction mode of an optical microdisk cavity. The motion with the string. We then show how these corre- of the string causes frequency fluctuations of the lations can be harnessed to improve the ability cavity mode which we readout using a quantum- to estimate weak forces applied on the string [4]. noise-limited laser locked on cavity resonance. These experiments verify long-standing pre- By operating the system at cryogenic temper- dictions of quantum theory and have deep rele- atures down to 1 K, we have been able to sup- vance to the operation of state of the art optical press all extraneous sources of classical frequency interferometers such as the Laser Interferometric fluctuations. This enables us to resolve the zero- Gravitational-wave Detectors (LIGO). Progress point motion of the string with a imprecision that is currently underway to translate some of the is 4 orders of magnitude smaller than its zero- techniques demonstrated on a table-top to the point motion. Heisenberg’s uncertainty principle km-scale interferometers of LIGO. predicts that such a measurement would lead to a disturbance of the string’s momentum – an effect References called quantum measurement back-action. We observe quantum back-action on the nanostring, [1] V. Sudhir, Ph.D. thesis, EPFL (2016) consistent with Heisenberg’s predictions [2]. We [2] D. Wilson, V. Sudhir et al., Nature 524, 325 then demonstrate a technique whereby the record (2015) of the measurement is used to perform feedback to cancel the disturbance due to quantum back- [3] V. Sudhir, D. Wilson et al., Phys. Rev. X 7, action. 011001 (2017) Another prediction of quantum theory is that [4] V. Sudhir, R. Schilling et al., Phys. Rev. X 7, in addition to the subject of a measurement un- 031055 (2017)
1E-mail: [email protected]
37 ISAMP TC-7, 6 8 January, 2018, Tirupati ID003 Chakraborty −
Ion-beam synthesis of metal quantum dots in glasses for nonlinear photonic Applications
Purushottam Chakraborty*
Saha Institute of Nuclear Physics Surface Physics and Materials Science Division Kolkata
Topic: D
Although electronics technologies have made great advances in device speed, optical devic- Ion implantation is found to be an attractive es can function in the time domain inaccessible to method for inducing colloid formation at a high electronics. In the time domain less than 1 ps, opti- local concentration unattainable by ‘melt-glass fab- cal devices have no competition. Photonic or optical rication process’ and for confining the non- devices are designed to switch and process light linearities to specific patterned regions in a variety signals without converting them to electronic form. of host matrices. Our recent works on metal-ion The major advantages that these devices offer are implanted colloid generation in bulk silica glasses speed and preservation of bandwidth. The switching have shown that these nanoclus ter–glass compo- is accomplished through changes in refractive index sites under favourable circumstances have signifi- of the material that are proportional to the light in- cant enhancement of (3) with picoseconds to tensity. The third-order optical susceptibility, (3) femtosecond temporal responses. The remarkable known as the ‘optical Kerr susceptibility’, which is achievements in developing such novel photonic related to the non-linear portion of the total refrac- materials seem to open the way for advances in all- tive index, is the non-linearity which provides this optical switching devices, e.g. in inducing metal- particular feature. Future opportunities in photonic colloids into coupled waveguides acting as a direc- switching and information processing will depend tional coupler. critically on the development of improved photonic materials with enhanced Kerr susceptibilities, as These ion-beam synthesized metal these materials are still in a relatively early stage of nanocluster-glass composites have been imaged development. using transmission electron microscopy (TEM), and confirmed using linear optical absorption (UV-Vis) Optically isotropic materials, e.g. glasses and Rutherford backscattering spectrometry (RBS). that have inversion symmetry, inherently possess Nonlinear refractive index and two-photon absorp- some third-order optical non-linearities. Although tion of these nanocomposites have been observed this is quite small for silica-glasses at = 1.06 m, using Z-scan, Degenerate Four-Wave Mixing the absorption coefficient is extremely low, thereby (DFWM) and Anti-resonant Interferometric Nonlin- allowing all-optical switching between two wave- ear Spectroscopy (ARINS) in the close proximity of guides, embedded in a silica fibre, simply by con- SPR wavelength of these metal nanoclusters. Both trolling the optical pulse intensity. Different glass sign and value of the nonlinear parameters have systems are under investigation to increase their been determined, and the third-order optical suscep- non-linearity by introducing a variety of modifiers tibility of the composites has been found to be sig- into the glass-network. The incorporation of semi- nificant. Such metal- glass nanocomposites having conductor micro-crystallites enhances the third- appreciable (3) with temporal responses in picosec- order optical response. Metal colloids or nanoclus- ond to femtosecond time domain have great rele- ters, embedded in glasses, have also been found to vance to futuristic switching materials in nanopho- introduce desired third-order optical non-linearities tonics. in the composite at wavelengths very close to that of the characteristic ‘surface-plasmon resonance (SPR)’ of the metal clusters.
______*[email protected]
38 ISAMP TC-7, 6 8 January, 2018, Tirupati ID004 Azuma − Recurrent fluorescence observed with an ion storage ring
Toshiyuki Azuma*† 1
* AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan † Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
Topic: D
For the last decade our understanding of the The criteria between the RF and black body cooling process of the isolated system in vacu- radiation (BBR) is also one of major concerns. um has been deepened dramatically. Especially, From this viewpoint, recent detection of re- the critical role of visible or near-IR photon current fluorescence visible photons [8] from - - emission from the electronic excited states after C4 and C6 stored in an electrostatic ion storage thermalization (not prompt fluorescence) has ring (TMU E-ring) is a milestone for the “RF been clarified experimentally. Historically, this photon spectroscopy”. Improvement of energy mechanism has been recognized by a variety of resolution in near future will give rich infor- fields (sometimes independently) for a long mation on transitions from the initial vibronic time. It is called by technical terms, like inverse state to other states accompanying the vibra- electronic relaxation, Douglas effect, recurrent tional excitation or de-excitation for several fluorescence (RF), or Poincaré fluorescence. modes. Furthermore, our group is now planning However, fluorescence from the thermally pop- an experiment for cold negative carbon cluster ulated electronic excited state is an appropriate ions stored in a newly developed cryogenic concept in the statistical treatment rather than a electrostatic ion storage ring, RICE (RIken picture of recurrence. Cryogenic Electrostatic ring) [9]. This device The RF process indeed reflects electronic re- will provide the initial condition of the electron- sponse and property of molecules, while vibra- ically and vibrationally ground state for the tional cooling emitting IR photons is deter- stored ions, and allows us to control their inter- mined mainly by the size and structure of the nal energy precisely by introducing energy- molecules. The RF rates are often orders of tunable lasers. magnitude higher than rates corresponding to IR vibrational transitions, and this fact has been References used for an experimental indication or evidence [1] P. Ferrari et al 2015 J. Chem. Phys. 143 224313 of the RF process. The first example is semi- [2] K. Hansen et al 2017 J. Phys. Chem. C 121 10663 + conductor cluster [1] of Sin and metal cluster [3] B. Kafle et al 2015 Phys. Rev. A 92 052503 and ref- + [2] of Aun . However, a drawback of such ob- erences therein; T. Sommerfeld 2010 J. Chem. Phys. 132 servation for detailed discussion is the fact that 124305 the property of the electronic excited level is not [4] S. Martin et al 2013 Phys. Rev. Lett. 110 063003; S. - well understood. The case of Al4 is also not ful- Martin et al 2015 Phys. Rev. A 92 053425, M. Ji et al ly understood although a theoretical prediction 2017 J. Chem. Phys. 146 044301 of very low-lying excited state for Al - was re- [5] G. Ito et al 2014 Phys. Rev. Lett. 112 183001; 4 N. Kono et al 2015 Phys. Chem. Chem. Phys. 17 24732 ported [3]. The second one is polycyclic aro- [6] V. Chandrasekaran et al 2014 J. Phys. Chem. Lett. 5 matic hydrocarbon (PAH) cations of anthracene, 4078; V. Chandrasekaran et al 2017 J. Chem. Phys. 146 naphthalene and pyrene [4], and the third one is 094302 - - carbon anion cluster [5,6] of C4 and C6 , where [7] J. U. Andersen et al 1996 Phys. Rev. Lett. 77 3991 their electronic property is available both from [8] Y. Ebara et al 2016 Phys. Rev. Lett. 117 133004 theory and experiment. A necessary condition [9] Y. Nakano et al 2017 Rev. Sci. Instrum. 88 033110 for the RF process is the large thermal popula- tion of the low-lying electronic excited state and the large oscillator strength. It is noted that cooling of C - has been explained by introduc- 60 ing collective electronic de-excitation [7], which
may be in the similar concept of the RF process. 1 † E-mail: [email protected]
39 ISAMP TC-7, 6 8 January, 2018, Tirupati ID005 Majumder − Tunable magic wavelengths of cooling and trapping with focused LG beam Anal Bhowmik and Sonjoy Majumder
Department of Physics, IIT Kharagpur, Kharagpur – 721302, India
Topic: D
Mechanisms of cooling and trapping of at- oms or ions using laser beam have been widely employed in high precision spectroscopic measurements. To minimize the various sys- tematics in the measurements of any spectro- scopic properties, experimentalists need to trap or cool the atoms at particular wavelengths of the external laser field where the differential ac stark shift of an atomic transition effectively vanishes, known as magic wavelengths. Determination of the magic wavelengths of al- kali-metal atoms for linearly polarized (i.e., spin angular momentum (SAM) equal to zero) laser sources have been well explored in litera- Figure 1. The designs of confining ions to regions of ture. Compared to the linearly polarized light, maximal or minimal light intensity for red- or blue- circularly polarized light (i.e., SAM=±1) has an detuned LG beam. extra part of the total polarizability, called the vector part, which arises due to the dipole mo- 2800 1058 4d3/2(+1/2) 4d3/2(+1/2) ment perpendicular to the field. For the circu- 2700 1056 ) ) 1054 m
2600 m n n ( ( 1052
h h t 2500 t g
larly polarized light, this vector part has some g 1050 n n
e 2400 l e l
e 1048 e v v
a 2300 a 1046 w
w
advantages in the evaluation of the valence po- c i
2200 c
i 1044 g g a a
M 2100 1042 M larizabiliy 2000 1040 100 102 104 106 108 110 1038 112 114 116 118 120 122 Polarizability (a.u.) Kuga et al. [1] was first realized Laguerre- Polarizability (a.u.) Gaussian (LG) based dipole trap with orbital 1048 9000 4d3/2(-1/2) 4d3/2(-1/2) angular momentum (OAM) and was confined 1047 ) 8000 ) m m n n ( (
7000 1046 h h t t g 10E+8 numbers of rubidium atoms to the core g n n e e
l 6000 l 1045 e e v v a 5000 a W of a blue-detuned vortex beam (see FIG). Sev- W 1044
c c i i g g
a 4000 a
M 1043 eral other recent experiments of trapping atoms M 3000 1042 use LG light beams suggest the importance of 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 Polarizability (a.u.) Polarizability (a.u.) the process even in blue-detuned region. Dur- ing the interaction of paraxial LG beam with Figure 2. Tuning of two magic wavelengths for o o o atoms or ions, which is below its recoil limit, 5sà4d3/2,mjfor angle 50 , 60 and 70 . (both OM=1) the lowest order transition is possible at quad- rupole level [2]. Therefore, we do not see the References effect of OAM of light on dipole polarizability. [1] T. Kuga, Y. Torii, N. Shiokawa, and T. Hirano, However, due to coupling of SAM and OAM, (1997) Phys. Rev. Lett. 78, 4713 . [2] P Mondal, B Deb and S Majumder (2014) Phys. Rev. the OAM of focused LG beam has significant A, 89, 063418 contribution on dipole transitions [3] and sub- [3] A. Bhowmik, P. K. Mondal, S. Majumder, and B. sequently to the dipole polarizability of atomic Deb (2016) Phys. Rev. A 93, 063852 system and tuning of magic wavelengths [4]. [4] A Bhowmik, N N Dutta and S Majumder, Submitted Phys. Rev A, Arxiv:1712:000xx
E-mail: [email protected], [email protected] 40 ISAMP TC-7, 6 8 January, 2018, Tirupati IE001 Wolf − Fast Ion Beams in a Cryogenic Storage Ring: Collisions and Internal Excitations
Andreas Wolf 1 for the CSR team
Max-Planck-Institut f¨urKernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
Topic E
Internal structures and excitations of atomic, In both cases, the rotational levels radiatively molecular and cluster ions are sensitively probed cooled towards populations dominated by J = 0. by their collisions and reactions. Ion–neutral Photodissociation and photodetachment cross- reactions, dissociative recombination with elec- sections as well as radiative lifetimes were in- trons, or electron emission from molecular and vestigated on the rotationally cold ions, stored cluster anions leave neutral products difficult to in empty space without buffer gas over times access with stationary targets. However, fast of up to 20 min. Recently, phase space cooling ion beams offer powerful single-particle detection of ion bunches circulating in the CSR was real- methods for observing neutral daughter prod- ized with the merged, velocity matched electron ucts. Using these efficient detection methods for beam. The first experiments at the facility using collisions of stored and possibly state-controlled laser and merged particle beam interactions and particles motivated the development of storage an outlook to planned studies will be covered. rings for atomic, molecular and cluster ions. In particular, electrostatic storage rings [1,2] were 2 K cryocooler Merged electron beam developed for complex, heavy ionic species with Ion beam diagnostics Laser interaction energies in the multi-keV range. Cryogenic storage ring that recently started Dipole operation at three laboratories world-wide [3, electrodes Reaction microscope 4,5] substantially improved the storage condi- (in development) tions and the control over internal ionic excita- tions. We here present the Cryogenic Storage Quadrupole Ring (CSR) at the Max Planck Institute for Nu- electrodes Ion injection and merged neutral beam clear Physics in Heidelberg, Germany [5]. It is 300 kV accelerator platform built to accept ion beams (cations and anions) Figure 1. Overview of the Cryogenic Storage Ring of kinetic energy up to 300 keV per ionic charge CSR (closed orbit circumference: 35 m) and stores these ions on a 35 m long closed orbit. The ion orbit comprises four 2 m long, field-free straight sections for collision experiments. The References ion energy is high enough to enable experiments with a merged electron beam at matched electron [1] S. Pape Møller and U. V. Pedersen, Phys. Scr. and ion velocities, even for polyatomic molecules. T92, 105 (2001). The merged electron beam, produced by a pho- [2] H. T. Schmidt, Phys. Scr. T166, 914063 (2015). tocathode, also enables phase space cooling of [3] H. T. Schmidt et al., Rev. Sci. Instrum. 84, ion beams stored in the CSR. Multi-particle co- 055115 (2013). incidence detectors operated downstream of the [4] Y. Nakano et al., Rev. Sci. Instrum. 88, 033110 merged-beam zones offer the detection of neutral (2017). products for collision kinematics analysis. The CSR was operated successfully at vac- [5] R. von Hahn et al., Rev. Sci. Instrum. 87, 063115 (2016). uum chamber temperatures of 6 K and ion beam storage time constants up to 45 min [5]. More- [6] A. O’Connor et al., Phys. Rev. Lett. 116, 113002 over, it was used for experiments on resonant (2016). photodissociation of cations (CH+ [6]) and near- [7] C. Meyer et al., Phys. Rev. Lett. 119, 023202 threshold photodetachment of anions (OH− [7]). (2017). 1E-mail: [email protected]
41 ISAMP TC-7, 6 8 January, 2018, Tirupati IE002 Schmidt − Elaborated Electron Beam Ion Sources for AMO Physics and Laboratory Astrophysics
1 2 Mike Schmidt∗ , Günter Zschornack∗†
∗ Dreebit GmbH, Großröhrsdorf, Germany † Dresden University of Technology, Department of Physics, Dresden, Germany
Topic: E. Development of major experimental facilities for AMO Physics and Laboratory Astrophysics
Electron Beam Ion Sources (EBIS) have been Dreebit also provides a superconducting EBIS proven as excellent sources of highly charged ions solution featuring electron beam currents of up for applications in research and development. to 500 mA at 6 Tesla magnetic field strength for Compared to the classical approach of producing very short ionization times at high ion output. highly charged ions, e.g. via stripping energetic low charged ions in costly ion accelerator struc- Table 1 lists some of the important ion source tures, EBIS provide a significant less complex parameters of the different Dreebit ion source and simplier way to generate ions of a broad var- models. ity of elements with almost all charge states Table 1. Important parameters of the Dresden Beams of highly charged ions extracted from EBIS models (magnetic field B, trap length L, max- EBIS usually feature a low emittance and low imum electron beam current Ie, maximum electron energy spread and can be used for very efficient beam energy Ee). post-acceleration, for surface analysis as well as EBIT EBIS-A EBIS-SC for surface modifications, just to name a few. B [Tesla] 0.25 0.6 6.0 However, EBISs are also excellent sources of L [mm] 20 60 200 photons (X-rays, ultraviolet, extreme ultravio- Ie [mA] 50 200 500 let, visible light) from highly charged ions. Ee [kV] 15 20 15
The ion production in each EBIS is based Complementing these unique ion sources on electron impact ionization in a high-density Dreebit provides complete Low Energy Facili- electron beam which is compressed in a strong ties (LEF) equipped with all required compo- axial magnetic field. nents ranging from the ion optics (e.g. lenses and deflectors) to the diagnostics (Faraday cups, The standard technique for the generation of Pepperpot emittance meters, Wien filters) but the required magnetic field for the electron beam also including the vacuum system and command formation and compression is the use of super- and control elements. conducting magnets making the EBIS setup so- phisticated and complex. A more pracictal way We will present these EBIS related technol- is the use of permanent magnets as it is realized ogy as a promising experimental facility for AMO in the patend-pending Dresden EBIS model fam- Physics and Laboratory Astrophysics. ily of the Dreebit [1] providing table-top EBIS machines with small spatial requirements and References low initial and operation costs. [1] Author V.P.Ovsyannikov, G.Zschornack 1999 RSI However, for high performance applications Vol 70 Page 2646-2651
1E-mail: [email protected] 2E-mail: [email protected]
42 ISAMP TC-7, 6 8 January, 2018, Tirupati IE003 Rajashekhar −
Design of an experimental facility for Molecular Science research using UV-VUV and soft X-ray photons
B.N. Rajasekhar* and Asim Kumar Das Synchrotron Beamline Development Section Atomic and Molecular Physics Division Bhaha Atomic Research Centre, Trombay, Mumbai – 400 085 & BARC beamlines section, B-1, Indus-1, RRCAT, Indore – 452013. E. Development of major experimental facilities for AMO Physics and Laboratory Astrophysics
Molecular Science research is being carried out using beamlines with different spectral characteristics at Indus-1, synchrotron radiation source (SRS), RRCAT, Indore [1]. An advanced beamline capable of delivering photons with high intensity photons at high resolution to study photon induced processes involving valence, intermediate and core electrons of atoms and molecules is under development at Indus-2 SRS [2]. This beamline uses a planar permanent magnet (PPM) undulator installed in the LS-2 Fig.1. Schematic of the VMI apparatus (not to scale) straight section of Indus-2 SRS [2] as the light showing repeller, extractor, and ground electrodes and relative distances source. A varied line spacing plane grating monochromator (VLSPGM) with a toroidal References: focusing mirror and four interchangeable 1. S K Deb et.al. J. Phys.: Conf. Series 425 gratings will be used to obtain monochromatic 072009 2013, http://www.rrcat.gov.in. light [3, 5]. To conduct advanced molecular 2. http://www.rrcat.gov.in/technology/accel/in Physics experiments such as Photo-ionization, dus2.html 3. Asim Kumar Das et.al. Ind. Jour. of Phys., photo-dissociation and photo-fragmentation of 88 1235 2014. molecules and clusters, an experimental station 4. A. K. Das, B N Rajasekhar and N K Sahoo, design has been modeled. This experimental BARC External Report – setup is based on velocity map imaging l(VMI) BARC/2014/E/008. technique with provisions to conduct time 5. P. K. Sahani et.al., “Radiation shielding for resolved and photon energy dependent imaging undulator beamline in Indus-2 synchrotron radiation source”, e - proceedings, spectroscopy of photo-electron and photo-ions RADSYNC – 2017, 19 -22, April 2017, produced in a photon molecule interaction. Fig.1 Ninth International Workshop on Radiation shows a schematic of the details of the VMI Safety at Synchrotron Radiation Sources, system. In this talk detailed design details of the held at NSRRC, Taiwan, DOI: electron & ion optics simulations, and energy http://radsynch17.nsrrc.org.tw/Documents/f resolution optimization of the experimental or-download/3-2-2. facility will be discussed. *Email: [email protected]
43 ISAMP TC-7, 6 8 January, 2018, Tirupati IE004 Safvan − Molecular Physics facilities at IUAC
1 C P Safvan∗ ,
∗ Inter University Accelerator Centre, New Delhi – 110067, India
Topic: E
The Inter University Accelerator Centre at to complex polyatomic aromatic hydrocarbons. IUAC is a centre set up under the University A variety of characteristic processes have been Grants Commission with a mandate to provide investigated: from production of excited target accelerator based experimental facilities to Uni- molecules to angular distribution of of the ionic versity students and faculty. In this talk we will fragments and intra-molecular bond formation. present a basic introduction to the Inter Uni- We will also describe new and upcoming fa- versity Accelerator Centre, with a special focus cilities at the LEIBF, for example a decelera- on the facilities available at the Low Energy Ion tor for ions has been developed and applications Beam Facility (LEIBF). In addition, IUAC pro- with very slow ions are being considered. Very vides high energy, heavy ion beams from the tan- slow irradiation of some biologically important dem and linear accelerators. molecules have been considered, and molecular The low energy ion beam facility at IUAC reaction investigations with a modified reaction provides ion beams from an Electron Cyclotron microscope is being designed. A new setup for Resonance source placed on a high voltage deck. the investigation of X-rays emitted in slow ion- This enables a wide range of energies and charge target (solids and gasses) is being actively pur- states to be available for experiments. Several sued. ion modification experiments are conducted reg- ularly for the materials science invetsigations. We will be modifying the existing time of There are also two beamlines available for atomic flight spectrometer (recoil ion momentum spec- and molecular physics experiments. trometer) to enable the measurment of electron The invesigations at the low energy facility energies and improve the resolution of the ions as at present are focussed on molecular dissociation well as expand the possibilities of the post collis- dynamics: on how the removal of several elec- sion charge state analyzer. trons from a stable molecule effects the disso- We will present a brief description of the ex- ciation dynamics. A variety of molecules have isting facilities, future plans, and invite all to use been investigated, from simple diatomics like N2 these facilities.
1E-mail: [email protected]
44 ISAMP TC-7, 6 8 January, 2018, Tirupati IE005 Kadhane − Plasma and beam diagnostics for electric propulsion research
Umesh R. Kadhane* 1
* Department of Physics, Indian Institute of space science and technology, Kerala, India
Topic: E.
Electric propulsion system (EPS) has complexities. These issues are aggravated by become a very important method of propulsion the fact that unlike the chemical thrusters which in space applications ranging from station can be tested for full life cycle in minutes and keeping of earth orbiting satellite to inter hours, EPS life cycle tests need to be done over planetary space missions. With increasing months. Since the theoretical modelling is not demand for reducing power requirement and very advanced due to complex plasma physics mass of spacecraft, and increasing the payload involved, the prototyping becomes a capability, EPS is at present a well established challenging task. In view of these difficulties, technology in space applications for in orbit the diagnostic systems become very essential propulsion. Among the electric propulsion for EPS research. The EPS plume consists of devices Hall Effect Thruster (HET) is two components, plasma and ion beam. Both recognized as the most attractive technique. It need to be studied using various plasma uses a low-pressure discharge with magnetically diagnostic and beam diagnostic tool. confined electrons to ionize and accelerate a At IIST several EPS diagnostic tools have propellant gas. been designed and developed. A few are well On comparison with the chemical known and well established tools like the counterparts, even though the electric Langmuir probe, Retarding Potential Analyzer propulsion thrusters are not capable of (RPA), ExB etc, and a few more complex providing high thrust, these thrusters can probes like parallel plate mass and energy deliver high specific impulse and have longer analyser, multispectral imaging, laser induced life as well is a good candidate for long duration fluorescence (LIF) etc. Most of these tools are missions and manoeuvres that require large now an integral part of ISRO's EPS research velocity increments. Inspite of these program. Details of the design, development, advantages, EPS is still a developing testing and operational usage, and important technology with several uncertainties and findings will be reported.
1 E-mail: [email protected]
45 ISAMP TC-7, 6 8 January, 2018, Tirupati IF001 Son − Ultrafast ionization and fragmentation dynamics of molecules at high x-ray intensity
1 Sang-Kil Son∗ ,
∗ Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
Topic: F
X-ray free-electron lasers (XFELs) have brought an impact on various scientific fields, including AMO physics, material science, astro- physics, and molecular biology. Understanding how matter interacts with intense x-ray pulses is essential for most XFEL applications. Ex- posed to an intense x-ray pulse, an atom within a molecule absorbs many photons sequentially and ejects many electrons, turning into a highly charged ion within a femtosecond time scale. This multiphoton multiple ionization dynamics differs from that at a third-generation x-ray synchrotron radiation source, where one-photon absorption is dominant, and from multiphoton strong-field ionization, where many photons are simultaneously absorbed to ionize a single elec- tron. The created charges are redistributed within the molecule, and then it explodes due to Coulomb repulsion. This fragmentation dy- namics occurs along with ionization dynamics. In this talk, I will present a theoretical frame- Figure 1. Upper panel: Average total molecular work to treat x-ray-induced processes and to charge as a function of fluence calculated for CH3I simulate detailed ionization and fragmentation molecules and within the independent-atom model. dynamics of atoms and molecules, introducing Lower panel: Illustration of the CREXIM mecha- two dedicated x-ray physics toolkits, xatom [1- nism in the molecular case, in comparison with the 4] and xmolecule [5-7]. With a joint ex- independent-atom case. perimental and theoretical study of small poly- atomic molecules irradiated by XFEL pulses, I will demonstrate how the theoretical model de- References scribes the essential mechanisms underlying ex- [1] Son S-K, Young L and Santra R 2011 Phys. Rev. plosion dynamics of molecules in intense x-ray A 83 033402 pulses. One of the key findings is that ioniza- tion of heavy-atom-containing molecules at high [2] Jurek Z, Son S-K, Ziaja B and Santra R 2016 J. Appl. Cryst. 49 1048 x-ray intensity is substantially enhanced in com- parison with that of isolated atoms. This is called [3] Rudek B et al 2012 Nature Photon. 6 858 charge-rearrangement-enhanced x-ray ionization [4] Toyota K, Son S-K, and Santra R 2017 Phys. Rev. of molecules (CREXIM) [7] as illustrated in Fig- A 95 043412 ure 1. The CREXIM effect plays an important [5] Hao Y, Inhester L, Hanasaki K, Son S-K and part in the quantitative understanding of XFEL– Santra R 2015 Struct. Dyn. 2 041707 molecule interactions and will need to be taken [6] Inhester L, Hanasaki K, Hao Y, Son S-K and into account for future XFEL applications. Santra R et al 2016 Phys. Rev. A 94 023422 [7] Rudenko A et al 2017 Nature 546 129 1E-mail: [email protected]
46 Abstracts of Contributed Talks ISAMP TC-7, 6 8 January, 2018, Tirupati CA001 KumarSunil − n+ Dissociation dynamics of N2 cations (n=1-2) and kinetic energy release study in the collision of 3.5keV electron with nitrogen molecule
Sunil Kumar, Suman Prajapati, Bhupendra Singh, B.K.Singh, R.Shanker1
Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi, INDIA -221005
Synopsis (Topic:A) We have performed an energy selected electron-ion coincidence experiment with 3.5keV continuous electron beam with free nitrogen molecule and have investigated inner shell processes which lead the formation of nitrogen dications. The kinetic energy release in their dissociation has been studied and the ob- tained results have been compared with the previously reported values by the other workers.
The study of dynamics and structure of intensity of the TOF mass peaks. A signature of 2+ 3+ Nitrogen and its cations (N2 , N2 ) is Resonant Auger (RA) excitation channel yield- important from both fundamental and ing the singly charged parent ion has been ob- applications point of view due to its importance served [2]. in the area of atmospheric science, controlled The details of the experimental methods and ob- fusion research, biophysics and several other tained results will be presented and discussed. branches of science. Inner shell processes play a . major role in the formation and understanding of double and multiple ionization of target atoms or molecules. Selected core-hole states have been created by excitation (ionization) with energetic electrons having kinetic energy 3.5keV. The electronic decay of the core-hole through auto-ionization or an Auger process is monitored by the analysis of energy selected ejected electrons while the chemical transformations of the precursor ion are observed with a time of flight (TOF) mass spectrometer[1]. The present study has two-fold objectives: firstly, to throw light on two types of core hole creation, namely, complete ionization and alternately the creation of a neutral core hole excited state by promoting the N 1s electron into the first unoccupied molecular orbital, the 1 Πg orbital and secondly, to provide detail information on the mechanism of formation and dynamics of dissociation of singly, doubly and possibly triply ionized molecular nitrogen ions Figure 1. Values of the kinetic energy released (KER) determined from our data are plotted as a function of the under impact of 3.5keV electrons with nitrogen binding energy (B.E.) for two different fragmentation molecules by performing coincidences between 2+ + + 2+ 2+ channels: N2 → N + N and N2 → N + N of a nitro- emitted electrons having three specified gen molecular dication formed in 3.5keV electron impact energies, namely, Ee = 343±4eV, 355±4eV, with N2 molecule. The lines connecting the data points 363±4eV and ions produced in an unimolecular are to guide eyes. collision reaction. From these measurements it has been possible to provide the details of References involved excited energy states which are formed to associate with the corresponding dissociation [1] S Kumar et al. Indian J Phys (July 2017) products on the basis of kinetic energy released 91(7):721–729
(KER) values for N 2+→ N+ + N+ 2+ 2 and N2 → [2] S Kumar et al. J.Phys.B (Under Review) N2++N channels as well as on the shape and
1 E-mail: [email protected] 48 ISAMP TC-7, 6 8 January, 2018, Tirupati CA003 Saha − Ultraslow isomerization in photoexcited gas phase C10−
1 K. Saha∗ , V. Chandrasekaran∗†, O. Heber∗, M. Iron‡, M. L. Rappaport§, D. Zajfman∗
∗ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 7610001, Israel. † Currently at Vellore Institute of Technology, Vellore 632014, India. ‡ Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel. § Department of Physics Core Facilities, Weizmann Institute of Science, Rehovot 7610001, Israel.
Topic: A Synopsis : Isomerization and carbon chemistry in the gas phase are key processes in many scientific studies. We report here on the isomerization process from linear C10− to its cyclic isomer in gas phase. We observed that, when the system is excited above its isomerization barrier energy, the actual isomerization from linear to cyclic conformation can take place in a very long time scale lasting hundreds of microseconds. Such slow isomerization rate is unusual in gas phase molecules and clusters.
Isomerization of polyatomic systems, such rate of photoexcited linear C10− at various pho- as, molecules and clusters, is a very basic phe- toexcitation energies (shown in Figure 1). The nomenon in nature. Isomerization in gas phase contribution of isomerization in the neutraliza- molecules is an important process in atmospheric tion rate is determined by a statistical model that chemistry and in interstellar medium. In the gas takes into account all the deexcitation processes. phase it is usually assumed that isomerization rates are governed by molecular dynamics when there is enough internal energy to reach differ- ent isomeric paths. Typical rates have the same time constant as rotation i.e., atomic motion rel- ative to the center of mass, which is of the or- der of picoseconds. Here, we present evidence of extremely slow isomerization rates for transi- tion from gas phase linear chain C10− cluster to its monocyclic ring conformation after photoex- citation above the isomerization barrier. Experiments are performed by trapping vi- Figure 1. Neutral counts from C10− as a function of brationally and rotationally excited C10− in a bent time after interaction with laser photons of various Electrostatic Ion Beam Trap (EIBT)[1]. The energies. The open markers show the experimental trapped ion beam is merged with an energy- data. The lines are from model calculations. The tunable laser beam. The neutrals flying out of dashed lines denote contribution from one-photon the trap, produced due to electron detachment excitation while the dotted ones are due to exci- from C10− , are recorded as a function of trapping tations by two photons. The solid lines represent time. the contribution from both and match well with the
When a large polyatomic system such as C10− , experimental data. is photoexcited, the excitation energy is quickly converted to vibrational energy due to internal Our results reveal that ultraslow isomeriza- conversion. The system may then deexcite via tion from linear C10− to monocyclic C10− is the various processes such as recurrent fluorescence, main reason behind production of neutrals last- infrared emissions, fragmentation, or by vibra- ing up to hundreds of microseconds after laser tional autodetachment in which neutrals are pro- excitation [2]. This finding may indicate a gen- duced due to delayed detachment of electrons. eral phenomenon that can affect the interstellar Depending on the internal energy of excited sys- medium chemistry of large molecule production tem, neutrals are usually formed after some de- along with other gas phase processes. lay with respect to photoexcitation. The neu- tralization rate is thus governed by the dynam- References ics of the excited system and can reveal great insights about various dexcitation processes. In [1] O. Aviv et al. 2008 Rev.Sci. Instrum. 79 083110 this study, we have measured the neutralization [2] K. Saha et al. 2017 Nature Physics (submitted) 1E-mail: [email protected]
49 ISAMP TC-7, 6 8 January, 2018, Tirupati CA006 KumarHerendra − Fragmentation dynamics of multiply charged OCS
1 2 Herendra Kumar∗ , Pragya Bhatt†, C.P. Safvan†, Jyoti Rajput∗
∗ Department of Physics and Astrophysics, University of Delhi, Delhi-110007, India. † Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110067, India.
Topic: A
In collisions of highly charged ions with neu- for two and three body dissociation channels. tral molecules one or more electrons can be re- The momentum correlation will be studied by us- moved from the target molecule by either ion- ing Newton diagrams. Further, the dissociation ization or electron capture. The molecule after mechanisms of OCSq+, (q=3-6) will be identified removal of electrons may dissociate into the con- by using Dalitz plot. For example, Dalitz plot of stituent atomic/molecular ions. We performed the triple-coincidence events of OCS3+ is shown an experiment in which a beam of multiply in fig 1. In this figure, we can see the signature charged ions 1.8 MeV Xe9+ are made to col- of concerted and stepwise processes. The events lide with neutral OCS molecules. At the colli- located along the cross diagonal structure indi- sion point electrons are released and the molecule cates break up pathway via two step processes gets multiply charged (i.e. OCSq+, q=1-8). The involving metastable CO2+ and CS2+. experiment was performed at the Low Energy Ion Beam Facility (LEIBF) of Inter University Accelerator Centre (IUAC), New Delhi, India. The technique of multi-hit recoil ion momentum spectroscopy employing a position sensitive mi- crochannel plate (MCP) detector was used to measure the time and position information of the recoil ions generated upon fragmentation of OCSq+. Electrons emitted during the interac- tion are used as timing reference for starting the data acquisition. The three-dimensional momen- tum vectors are derived from the measured time of flight and position information of the detected fragment ions. The multi-hit capability of the setup aids in gaining knowledge about the par- ent ion from which these fragments originate. For more details of experimental setup see ref- erence [1]. The aim of this study is to explore q+ Figure 1. Dalitz plot of OCS3+ ion dissociating the dissociation pathways of OCS ion. 2 + + + pi into (C + O + S ) channel, where i= , pi, We have identified complete two and three k body dissociation channels of OCSq+ from the and i are the momentum and kinetic energy of the th 2 double and triple ion coincidence maps. The i fragment; k= pi is the total kinetic energy. 2+ Concerted process makes up the bulk of the im- dominant two body dissociation channels are S P + CO+, CO+ + S+, CO2+ + S+, and CO2+ + age while stepwise processes involving metastable S2+. Many three body dissociation channels are CO2+ and CS2+ are shown by X-shape structure. observed as Cl+ + Om+ + Sn+, where l, m, & n range from 1 to 3 and l+m+n=q. In this presentation, the kinetic energy re- References lease (KER) distribution, momentum correla- tion, and angular distribution will be discussed [1] Kumar et al., 2014 J. Mass Spect. 374 44-48.
1E-mail: [email protected] 2E-mail: [email protected]
50 ISAMP TC-7, 6 8 January, 2018, Tirupati CA035 Mandal − Isomerization of Acetylene doped in He nanodroplets by EUV synchrotron radiation
1 Suddhasattwa Mandal∗ , Ram Gopal‡, Sivarama Krishnan†, Robert Richter¶, Marcello 2 Corenok, Hemkumar Srinivas††, Alessandro D’Elia∗∗, Vandana Sharma§
∗ Indian Institute of Science Education and Research Pune, Pune - 411008, Maharashtra, India ‡ TIFR Centre for Interdisciplinary Sciences, Hyderabad - 500107, Telangana, India † Indian Institute of Technology Madras, Chennai - 600036, Tami Nadu, India ¶ ElettraSincrotrone Trieste, Area Science Park, 34149 Trieste, Italy k Consiglio Nazionale delle RicercheIstituto Officina dei Materiali, Laboratorio TASC, 34149 Trieste, Italy †† Max-Planck-Institut f¨urKernphysik, 69117 Heidelberg, Germany ∗∗ University of Trieste, Department of Physics, 34127 Trieste, Italy § Indian Institute of Technology Hyderabad, Sangareddy - 502285, Telangana, India
Topic: A
The effect of environment in the molecu- photoion-photoion coincidence measurement en- lar isomerization process, which is an important abled us to gain insight into the isomerization chemical process happening in nature, remains process followed by fragmentation. an intriguing object of investigation. Acetylene We have not observe any substantial ion yield cation [HC = CH]+ is a well studied molec- of CH+ at 17eV photo energy, it seems the 2 ∼ ular ion in which isomerization occurs through isomerization process is suppressed by the He H atom migration from one C atom to other C matrix. However we observed a small ionization atom upon absorption of EUV radiation[1]. peak of acetylene at 21.6eV photon energy which We have studied the isomerization of acety- seems to be through Penning ionisaion process. lene molecule embedded inside the Helium nan- We have also recorded the photoelectron odroplets under synchrotron radiation at the Gas spectra along with the angular distribution of Phase beamline of Elettra synchrotron facility, the photoelectron with the polarization axis of Italy. The cold environment ( 0.35K) of He the synchrotron radiation in coincidence with the ∼ nanodroplet serves as an ideal host matrix for photoions for gas phase isolated acetylene at pho- spectroscopic study of rovibroically cold embed- ton energies (20 25eV ). The photoelectron an- − ded molecules. Ionisations of dopant molecule gular distributions are fitted with the equation via Penning process and charge transfer ioniza- tion are important processes upon photoexci- N(θ) = N0(1 + βP2(cosθ)) taion of the He nanodroplets at photon energies (20 25eV )[2,3]. The isomerization of gas phase where θ is the angle of the emitted electrons with − polarization axis and β is the anisotropy param- isolated acetylene occur at an energy of 17eV ∼ eter which depends on the state of the molecule [1] which is well below the photoexcitation energy from which the molecule is ionized. of He nanodroplets, therefore He nanodroplet en- vironment is expected to play an important role in the isomerization process. References We have recorded the photoelectrons with [1] Y. H. Jiang et al. 2010 Phys. Rev. Lett., 105, a Velocity Map Imaging (VMI) spectrometer in 263002 coincidence with the photoions detected with a Time of Flight (TOF) mass spectrometer for pho- [2] D. Buchta, S. R. Krishnan et al. 2013 J. Phys. ton energies (20 25eV ). The signature of iso- Chem. A, 117, 4394 − + merization in acetylene is the CH2 ion yield. [3] D. Buchta, S. R. Krishnan et al. 2013 J. Chem. The mass correlated photoelectron spectra and Phys., 139, 084301
1E-mail: [email protected] 2E-mail: [email protected]
51 ISAMP TC-7, 6 8 January, 2018, Tirupati CA049 Shastri − Vacuum ultraviolet photoabsorption spectroscopy of anisole
Aparna Shastri 1, Asim Kumar Das and B.N. Raja Sekhar 2
Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
Topic: A. Quantum collisions and spectroscopy of atoms, molecules, clusters and ions
The spectroscopy of benzene and its deriva- in the region up the first IP as well as above the tives have attracted much attention over the first IP up to the third IP at ~ 11.06 eV. years as they are the building blocks for the more complex polycyclic hydrocarbons (PAHs) which play an important role in atmospheric and interstellar chemistry [1]. They also consti- tute chromophores in larger biological mole- cules like DNA bases [2]. Anisole or methoxy benzene (C 5H6OCH 3) is one of the building blocks of lignin, a major component of biomass and plant cell walls [3]. The radicals formed in the pyrolysis of anisole are important in under- standing combustion processes and soot forma- tion, relevant to environmental chemistry [3,4]. Recently, it has also been studied as a promis- ing fluorescent tracer in gas phase imaging di- agnostics [5]. Figure 1. UV–VUV Photoabsorption spectrum of A thorough knowledge of the ground and ex- Anisole recorded using synchrotron radiation. cited state electronic structure of a molecule is a Interpretation of the observed transitions as prerequisite to understanding its photochemistry valence/Rydberg/charge transfer type, potential at a molecular level. From this perspective, vi- energy curves of the first few excited states with brational spectroscopy of anisole and hydrogen respect to specific bond stretching coordinates bonding have been studied quite extensively in and other related issues are addressed with the the ground state [6]. Studies on the excited elec- help of DFT and TDDFT calculations on tronic states however are essentially confined to ground and electronically excited states. Ex- the first excited (S –S ) system in the UV re- 0 1 perimental details, computational methodologies, gion [6]. The only report of its VUV absorption results and analysis will be discussed. spectrum [7] is limited to the region below 64,000 cm -1 (~7.9 eV) and does not give a com- References plete spectral analysis. [1] A.M. Scheer et al. 2010 J. Phys. Chem. A 114 In the present work, we report a study of the 9043 photoabsorption spectrum of anisole in the UV- [2] D. J. Hadden et al. 2011 Phys. Chem. Chem. -1 VUV region (40,000–95,000 cm ) using syn- Phys. 13 4494 chrotron radiation (cf . Figure 1). Experiments [3] H. Xu et al. 2013 J. Phys. Chem A 117 12075 are performed using the Photophysics beamline [4] B. Shu et al . 2017 Int. J. Chem Kinet 49 656 at the 450 MeV storage ring Indus-1 [8]. The [5] S. Faust et al. 2013 Appl. Phys. B 112 203 first ionization potential (IP) of anisole has been [6] L. J. H. Hoffmann et al. 2006 Phys. Chem. reported at 8.21 eV [9], suggesting the presence Chem. Phys. 8 2360 and references therein. et al. Mol. Phys. 9 of Rydberg series starting from ~ 4.8 eV. How- [7] K. Kimura 1964 117 [8] N.C. Das et al. 2003 J. Optics (India). 32 169 ever, in spectra of benzene derivatives, Rydberg [9] T. Kobayashi et al . 1974 Bull Chem Soc Jap 47 states often appear as weak features superim- 2563 posed on stronger valence/charge transfer bands [10] K. Sunanda et al. 2016 J. Quant. Spectrosc. [10]. In the present experimental work, we ob- Rad. Transf. 184 89 serve several new, hitherto unreported features
1 E-mail: [email protected] 2 E-mail: [email protected]
52 ISAMP TC-7, 6 8 January, 2018, Tirupati CA051E Soumyashree − Elemental analysis using Laser Induced Breakdown Spectroscopy
Swetapuspa Soumyashree1, Prashant Kumar, Rajesh K Kushawaha, S B Banerjee, K P Subramanian
Physical Research Laboratory Ahmedabad – 380009, Gujarat, India
Topic: A (or E)
The conventional LIBS algorithm is not ade- quate to analyse dense LIBS spectra as in case of steel sample. A novel technique based on fit- ting the synthetic spectra onto the LIBS spectra has been developed and is found to be success- ful in estimating the accurate elemental compo- sition in such samples.
The method automatically incorporates the ef- fect of self-absorption in LIBS plasma while generating synthetic spectrum. All other plasma parameters are directly obtained from the rec- orded emission spectra. Plasma neutrality con- dition is used to normalize the individual num- ber densities and estimate the absorption path length. This procedure is found to be successful for achieving convergence of retrieval algorithm This algorithm was used in analysis of various even for dense spectrum as well as for resolving rock samples which confirms the presence of merged lines with accuracy. The experimental elements like Ca, Al, Fe, Mn, Na, O, Pb, Si and LIBS spectra fitted with a synthetic spectrum is Ni in those samples. The detailed quantitative shown in the following figure for steel sample. study on these samples using the developed al- gorithms will be presented. We have also developed an automated search algorithm to identify emission lines for un- References known samples using NIST database. [1] Prashant Kumar, et al, to be published
1E-mail: [email protected]
53 ISAMP TC-7, 6 8 January, 2018, Tirupati CB003 Majety − Multielectron effects in strong field ionization of few electron molecules
Vinay Pramod Majety*†1 and Armin Scrinzi*
* Department of Physics, Ludwig Maximilians University, 80333 Munich, Germany † Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
Topic: B
Strong field ionization is at the heart of polarization, dynamic exchange, multiple various ultrafast imaging techniques such as orbital ionization and interchannel coupling will high harmonic imaging, molecular orbital be discussed [2,3,4]. tomography and laser induced electron diffraction. Computational modeling of these processes is a major challenge as it involves solving the many body Schrodinger equation in References a non-perturbative way. [1] VP Majety et al. 2015, New Journal of Physics We report here the hybrid anti-symmetrized 17, 063002 coupled channels approach [1], a recent [2] VP Majety and A Scrinzi 2015, Physical Review development in this context. In conjunction Letters 115, 103002 with the other established techniques such as [3] VP Majety and A Scrinzi 2015, Journal of complex scaling and the time dependent surface Physics B: Atomic, Molecular and Optical Physics flux method; we will present a detailed study of 48 (24), 245603 [4] VP Majety and A Scrinzi 2017, arXiv preprint photoemission from CO2 molecule following strong field ionization by few cycle near-IR arXiv:1709.00721 (accepted in Phys Rev A) laser fields. The role of multi-electron
†1 E-mail: [email protected]
54 ISAMP TC-7, 6 8 January, 2018, Tirupati CB005 Sainadh − Tunneling delays in strong field ionization of atomic hydrogen
U Satya Sainadh* 1, Han Xu* 1, X. Wang § 2, Atia-Tul-Noor* 1, William C. Wallace* 1, N. Douguet† 3, Igor Ivanov ‡ 4, Klaus Bartschat† 3, Anatoli Kheifets¶ 5, R.T. Sang * 1, Igor Litvinyuk* 1.
* Australian Attosecond Science facility, Center for Quantum Dynamics, Griffith University, Brisbane QLD , Australia. §School of Nuclear Science & Technology, Lanzhou University, Lanzhou, 730000, China. † Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311, USA. ‡Center for Relativistic Laser Science, Institute for Basic Science, Gwangju 500-712, Republic of Korea. ¶Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200, Australia.
Topic: B
Synopsis We present the results [1] of tunneling delays measured using attosecond angular streaking of atomic Hydrogen using elliptically polarized, 6 fs pulses that are centered around 770 nm, within the intensity range of 1.65 to 4 X 1014 W/cm2 . We find a strong agreement in these results with the solutions of complete 3D-TDSE simulations. Further, we compute the contribution of coulomb effects (between the ionized electron-parent ion) to the measured angular offsets using Yukawa potential, subtracting which yields the real ‘tunneling delays’.
The ’attoclock’ technique [2] employs near- Further, using simulations with Yukawa potential circularly polarised few-cycle femtosecond pulses, we present the contributions of coulomb potential to and is used in measuring tunnelling delays under the angular offsets. We finally present an upper strong field ionisation. The peak of the circular field bound for ‘tunnelling delays’. ionises the electron and the ionised electrons get streaked in the residual (post-peak) circular field of . light mapping the instant at which electrons appear in the continuum to its final momentum. Thus the time difference between the instant of peak electric field and the instant at which electron appears in the continuum, respectively is gives us the tunnelling delays. The time-difference materialises as an an- gular offset in the photo-electron momentum distri- bution in the polarisation plane relative to the polar- isation ellipse of the light.
Although previous attoclock experiments [2,3] hinted at zero-tunnelling delays, exact theoretical Figure 2: Experimental data of momentum distribution of solutions were not available to study the ionisation photoelectrons in the polarisation plane [1]. A corre- dynamics in detail. Atomic Hydrogen (H), being the sponds to the peak electric field and B & C are the ex- pected and measured peaks of photoelectron-momentum simplest atomic system for which a complete solu- distribution in the polarisation plane tion of 3D-TDSE is available analytically without requiring approximations beyond the dipole approx- imation in the non-relativistic regime can enable us to benchmark the field. It can be later used to vali- References date various theoretical models that help us in un- [1] U. Satya Sainadh et. al. 2017 arXiv:1707.05445; derstanding ionisation dynamics in complex atomic U Satya Sainadh et al 2017 J. Phys.: Conf. Ser. 875 systems. 022039. [2] P. Eckle et.al. 2008 Nat. Phys. 4, 565 We performed the attoclock experiment with H us- [3] A.N. Pfeiffer et.al. 2013 Phys.414, 8491 [4]. J.P. Schwonek, 1990 PhD thesis, Massachusetts In- ing COLTRIMS and 770nm, 6fs pulses at intensi- stitute of Technology, Cambridge, A. ties from 0.165-0.39 PW/cm2. The H gas jet source [4] is an RF-discharge tube that dissociates H2 with a dissociation fraction of 60%. A comparison with full 3D-TDSE codes is done and a strong agreement is found between the experiment and the theory.
1 E-mail: [email protected] 55 ISAMP TC-7, 6 8 January, 2018, Tirupati CC001 Acharya − PC based Acousto Optic modulator Driver for Cold Atom Interferometer
Aishik Acharya * 1, R. Bharadwaj Reddy#, Manisha Bajaj*, Akash Kamoji*, Shruthi P. Michael*, Anu- radha Anarthe * and D. Revathi*
* Electro Optical Instrument Research Academy, Hyderabad – 500069, Telangana, India #Department of Instrumentation & Control Engineering, Manipal Institute Of Technology, Manipal-576104, Karnataka, India
Topic: C
Cold atom interferometry can be done by laser Thus it is clear that an RF field with control- cooling of neutral atoms. In our experimentation lable amplitude and frequency is required for de- cold atom cloud will be generated by cooling Ru- sired amount of light diffraction precisely. Con- bidium-87 atoms in a magneto optical trap. Six ventional function generators can be used to gen- counter propagating laser beams (in 0, 0, 1 con- erate this. But for miniaturized and control appli- figuration) will be used for laser cooling from a cation such devices are not suitable to work with. detailed optical setup (figure 1). To control the An universal driver circuit for driving the AOMs laser frequency precisely for cooling trapping has been developed for this purpose. The module and detection Acousto optic modulator (AOM) is requires an external frequency reference of 10 used. In this paper we have proposed a simple MHz which is used as the clock frequency of Di- control electronic driver circuit for AOMs to rect Digital Synthesizer. A micro controller in- control the laser frequency precisely. terface has been developed to feed the control word to the DDS and control a variable attenua- tor digitally. A detailed block diagram is shown in the figure 2. A computer interface based on LabView platform has been developed which communicates with the microcontroller over USB to UART interface for controlling the RF frequency and amplitude in closed loop opera- tion. This helps to control the laser frequency and intensity sequentially during cooling, trapping and repumping cycles of Rb-87 atoms.
Figure 1. Block diagram of optics setup
In acousto optic modulators (AOM) the acousto optic effect is used to diffract and shift Figure 2. Basic block diagram for RF driver circuit the frequency of the light using sound waves. In side of an AOM a piezo electric transducer is at- References tached to a quartz material. An RF signal is used [1] “An electronic sequence controller for the Cs to drive the transducer to vibrate which in turn fountain frequency standard developed at CSIR-NPL produces acoustic wave inside the material. This India”, S. Yadav, A. Acharya, P. Arora and A Sen causes change in refractive index of the material. Gupta, Measurement 75 (2015) 192–200. Incoming light scatters off the resulting periodic [2] "A Guide to Acousto-Optic Modulators" index modulation and interference occurs similar (http://massey.dur.ac.uk/resources/slcornish/1. to Bragg diffraction. The process acts like three AOMGuide.pdf) wave mixing resulting in sum and difference of frequency generation between phonons and pho- 1 E-mail: [email protected] tons.
56 ISAMP TC-7, 6 8 January, 2018, Tirupati CC004 Kundu − Two Components Bose-Einstein Condensate in a Frustrated Optical Lattice Nilanjan Kundu* 1, Utpal Roy* 2
* Department of Physics, Indian Institute of Technology Patna, Bihta, Patna-801103
Topic: C
Keyword: Bose-Einstein Condensation, Bichromatic Optical Lattice, Rogue waves
We contribute to the field of rogue waves by is mapped to the Manakov equation which in turn providing an exact analytical model of the coupled gives an exact solution of bright-dark soliton mix- Bose-Einstein Condensation (BEC) in Bichromatic ture dependent on the periods of the potential. Optical Lattice (BOL). We start with the dimen- sionless 1D BEC of a weakly interacting ultra cold atomic gas with cubic nonlinearity, under the influ- ence of one-dimensional spatial BOL. Our main goal is to solve the two-component Gross Pitäevskii (GP) equation which is the modified form of Non Linear Schrӧdinger Equation (NLSE) for different types of potentials and nonlinearity. Although it is quite nontrivial to develop analytical techniques for these nonlinear systems, improvement of different methodologies in PDE makes it possible to map the equation to a known localized solution and observe their dynamics for various potentials. Rogue waves, topic of intense research, are extreme wave events mostly familiar for its large scale maritime disas- ters. This kind of waves is related with oceanic phenomenon. Apart from the fact that physicist have shown their existence in different systems: optics[1], plasmas, capillary waves and BEC, new studies related with the solution of the correspond- Figure 1:A typical variation of the potential and den- ing PDE having special properties of correlated so- sities of two components lutions are of severe need. Manakov system is a special kind of system which gives the coupled Ro- References gue wave solutions [5]. These type of solutions are basically the mathematical description of pedegrine 1. D. R. Solli, et al., 2007, Nature (London), soliton, which is localized in both the coordinates 450, 1054 and is a rather mixture of dark-bright solitons. 2. Manikandam, et al., 2016, Phys. Rev. E, 93, These types of multicomponent systems [2] were 032212 3. A. Nath, U. Roy, 2014, Laser Phys. Lett, 11, first experimentally realized in Rubidium atoms, 115501 where interatomic interaction brings out a number 4. A. Nath and U. Roy, 2014, J. Phys. A: Math. of interesting physical phenomena. Here we con- Theor, 47, 415301. centrate on a coupled GP equation under external 5. A. Degasperis, et al.,2012, Phys. Rev. Letter, confinement i.e. frustrated optical lattice [3,4]. Af- 109, 044102 ter deriving the consistency conditions related to the phase, amplitude and nonlinearity, the GP equation
1 E-mail: [email protected] 2 E-mail: [email protected]
57 ISAMP TC-7, 6 8 January, 2018, Tirupati CC007 Rajauria − Nonautonomous matter-waves in a quasi-one-dimensional waveguide geometry
Parth Rajauria , Thokala Soloman Raju 1
Department of Physics, IISER Tirupati, Tirupati – 517507, Andhra Pradesh, India
Topic: C:
In this paper, we use a variant of much discussed following set of differential equations: nonlinear Schrodinger¨ (NLS) equation or modified 2 Gross-Pitaevskii (GP) equation with an external ∂ Φ(η) 5 µΦ(η) = + σΦ (η) + s0 (3), source. This equation features prominently in the − ∂η2 description of pulse propagation through asymmetric ηxx = 0, ηt + θxηx = 0, (4) twin-core fibers [1, 2], charge-density waves in con- 2 2ρt + ρ(θxx 2γ) = 0, 2s(t) s0ρηx = 0, (5) dense matter physics and long-Josephson junctions. − − 2g(t)ρ4 ση2, 2v(x, t) + µη2 + θ2 + 2θ = 0. (6) Although, pulse propagation in single-core waveg- − x x x t uides is widespread, the study of self-similar waves We have obtained a fractional-transform soliton solu- in dual-core waveguides is limited. In the quasi-one- tion of Eq. (1) using the ansatz in Eq. (2). We have dimensional or higher-dimensional NLS or GP equa- numerically checked the stability of this solution for tions with space-time modulated parameters may different values of the strength of quintic nonlinear- generate rich nonlinear structures such as nonau- ity and inhomogeneous source, using the split-step tonomous solitons, resonant solitons, and breathing Fourier transform method. For t=20, we have ob- or oscillatory solitons. Here, we analytically and nu- tained chaotic behavior of this exact solution. But, merically explore nonautonomous matter-waves that for t=10, we have obtained an oscillatory solution for describes the transport of Bose-Einstein condensed the parameter values specified in the figure caption. atoms from a reservoir to a waveguide, in the pres- Finally, we hope that these newly found matter- ence of longitudinally modulated repulsive quintic wave solutions may further raise the possibility nonlinearity, gain, and an inhomogeneous source. of some experiments and potential applications to Pertinently, we have considered a model that sim- BECs in the presence of externally driven source. ulates the coupling of a reservoir of Bose-Einstein condensed atoms and the waveguide in a quasi-one- dimensional geometry. Here, the condensate at a par- ticular chemical potential is injected into the waveg- uide from a reservoir at some distance say x0. The reservoir emits plane matter waves in both direc- tions into the waveguide. Such a scenario can be well captured by the following modified GP equa- tion with space-time modulated potential, inhomoge- neous source, quintic nonlinearity, gain or loss term given by [3]
∂ψ ¯h2 ∂2 Figure 1. Numerically simulated oscillatory solution of i¯h = + V (x, t) + g(t) ψ 4 + iΓ(t) ψ + ∂t −2m ∂x2 | | Eq. (1) for g = 0.1 and the strength of the source is s = 0.05 with a dc-offset 0.05. S(t)exp[iϕ(x, t)]. (1) 0
In order to find the exact nonautonomous solutions of Eq. (1), we use the following multivariate trans- References formation: [1] G. Cohen 2000 Phys. Rev. E 61 874 iθ(x,t) ψ(x, t) = ρ(t)e Φ[η(x, t)]. (2) [2] T.S. Raju et al. 2005 Phys. Rev. E 71 026608 Substitution of this ansatz into Eq. (1) results in the [3] T. Paul et al. 2005 Phys. Rev. Lett. 94 020404
1E-mail: [email protected]
58 Abstracts of Contributed Posters ISAMP TC-7, 6 8 January, 2018, Tirupati CA002 Singh − Measurement of the angular distributions of thick target bremsstrahlung pro- duced by 10-25keV electrons incident on thick Ti & Cu pure elements.
Bhupendra Singh*, Suman Prajapati*, Sunil Kumar*, Bhartendu Kumar Singh*, Xavier Llovet†, R shanker*1
*Atomic Physics Laboratory, Department of Physics, Banaras Hindu University, Varanasi 22100, India † Scientific and Technological Centers, University of Barcelona, Lluís Solé i Sabarís, 1-3, 08028 Barcelona, Spain
Topic:A
Recent experimental and theoretical studies on angular distribution of bremsstrahlung (BS) photons produced from 10-25keV electrons in- cident on thick targets of Ti and Cu have been made in our laboratory by using Si-PIN photo- diode detector [1]. The angular measurements was obtained by changing the incidence angle (α) measured between the direction of incident electron & normal to the target surface while the photon detector was fixed perpendicular to the electron beam direction in reflection geome- try. The Double differential bremsstrahlung yield (DDBY) was obtained for both Cu and Ti
thick targets for the impact energy at 10, 15, 20 Figure 1. Comparison of the experimental data of and 25keV and the incidence angle varies in relative DDBY with the MC [3] calculations as a range between 150-750 with an angular uncer- function of incidence angle α: a) k=4keV and b) 0 7keV photons produced in 10keV electron impact tainties of (±5 ). with a thick Ti target; c) k=3keV and d) 7keV pho- Angular distribution of DDBY for Cu & Ti tons produced in 15keV electron impact with a targets; clearly shows the anisotropic distribu- thick Cu target respectively. tion of bremsstrahlung photons. This anisotropy is large for high photon energy and small for low photon energy. As the low photon energy References: emitted from deep inside the target, considera- [1] Bhupendra Singh et.al. (2017), communicated in ble amount of absorption occurs which exhibit Rad. Phy. and Chem.. the smallness of anisotropy while the high ener- [2] L.Kissel et.al., (1983). At. Data Nucl. Data Tables gy photons emerges from the surface of the tar- 28, 381–460 get and gives large anisotropic distribution of [3] Xavier Llovet et.al., (2017), Microsc. Microanal. photons like thin targets [2]. The anisotropy for 23, 634-646. Ti is 6% larger than Cu for low energy photons and 11% smaller for high energy photons for given impact energy. The nature of the angular distribution of thick target BS also shows the dependency on the atomic number of the ele- ments. Calculated DDBY of Cu and Ti thick tar- gets have been compared with the predictions from the general purpose PENELOPE MC cal- culations [3].The agreement between experi- ment & theoretical predictions is found to be satisfactory within the uncertainties involved in the measurements (~6%).
1E-mail: [email protected]
60 ISAMP TC-7, 6 8 January, 2018, Tirupati CA004 Priti − Xenon Plasma Modeling with Relativistic Fine Structure Cross Sections
Priti 1, Lalita Sharma and Rajesh Srivastava
Department of Physics, IIT Roorkee, Roorkee – 247667, Uttarakhand, India
Topic: Quantum collisions and Spectroscopy of atoms, molecules, clusters, and ions.
The electron impact excitation cross section bound state wave functions are calculated by data for xenon have great importance as they using GRASP2K [6]. Thereafter, static distor- are key component to Xe-plasma models devel- tion potential is obtained and the coupled Dirac oped for several applications viz. mercury-free equations are solved numerically to calculate fluorescent lighting and flat-panel plasma dis- the wave functions of both the initial and final plays, in particular for characterization of xenon channels for the projectile electron. Analytic fed thruster plasmas [1]. In order to correctly fitting of the calculated cross sections are also characterize the plasma to obtain reliable plas- obtained so that these can be directly used in ma parameters viz. electron temperature elec- any plasma model. Utilizing the obtained cross tron density etc. we need to incorporate in colli- sections we are developing a reliable CR model sional radiative (CR) plasma model with com- for diagnostics of hall thruster Xe plasma. The plete set of vast and consistent fine structure model incorporates various population transfer electron excitation collision cross sections data mechanisms among fine structure levels such as in the wide range of incident energy. We have electron impact excitation, ionization, radiative been putting continuous efforts through our se- decay along with their reverse processes such as ries of calculations for electron-impact relativ- electron impact de-excitation, three body re- istic excitation cross sections for several fine combination. The population density of differ- structure transitions in rare-gas atoms viz. Ar, ent fine structure states is being obtained by Kr, Xe [2-5]. Using our calculated complete set solving the rate equations for all states simulta- of cross section data we have successfully de- neously which interconnects the different popu- veloped CR models for Ar and Kr. lating and depopulating channels among the fi- ne-structure levels. All the results for cross sec- In the continuation to our earlier work, now tions and plasma parameters will be presented we focus in the present work on developing a and discussed in the conference. suitable CR model for Xe-plasma and obtain a complete set of electron impact excitation cross section data for different fine structure transi- References tions in addition to the previously reported cal- culations [3-5]. [1] RA Dressler et al., 2009 J. Phys. D: Appl. Phys. 42 185203 In this regard, a systematic calculation of the electron impact excitation of Xe has been done [2] LC Pitchford et al., 2017 Plasma Process Polym 14, using fully relativistic distorted wave theory. A 1. complete set of consistent cross sections are [3] R Srivastava et al., 2006 Phys Rev. A 74, 012715. calculated for various transitions from its ground (5p6) to other higher lying fine structure [4] L Sharma et al., 2011 Eur. Phys. J. D 62, 399. states (in Paschen notations) 1si, 2si (i=2-5), 2pi [5] L Shama et al., 2009 Journal of Physics: Conference (i=1-10), 3p (i=1-6), 3d (i=1-12), inter transi- i i Series 185 012042. tion among all 1si fine structure states to 2pi , 3pi and intra transition among 1si and 2pi in the [6] P. Jönsson, et. al.,2007 Comput. Phys. Commun. electron impact energy range from the excita- 177,597. tion threshold to 1keV. For this calculation, the multi-configurational Dirac-Fock (MCDF)
E-mail: [email protected]
61 ISAMP TC-7, 6 8 January, 2018, Tirupati CA005B Mandal − SOIAIC effect on Wigner-Eisenbud-Smith time delay: Xe 4d photoionization
1 †,#2 A. Mandal∗ and P. C. Deshmukh
∗ Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India † Department of Physics, Indian Institute of Technology Tirupati, Tirupati, 517506, India # Department of Physics, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
Topic: A, B
Photoionization is a many body process. An ap- A particular illustration of interchannel coupling propriate description of the mechanism needs to in- effect is with reference to dipole channels originat- clude important electron-electron correlations [1]. ing in spin orbit split initial states [5,6]. The Interchannel coupling between different dipole and effect of SOIAIC (Spin Orbit Interaction Activated also non-dipole channels are important in describing Interchannel Coupling) on WES (Wigner Eisenbud photoionization observables [2]. Smith) time delay [7] is investigated for a moderate 4 d 3 / 2 Z atom [Z=54, Xe], and furthermore, the angle de-
8 0 0 0 t d _ 4 d 3 / 2 _ 1 / 2 _ p _ 0 _ P I P T pendence of SOIAIC effects on WES time delay is t d _ 4 d 3 / 2 _ 1 / 2 _ p _ 0 _ I S S T
) investigated here. 3 0 0 s 6 0 0 0
a Some illustrative results are shown in Fig. 1, the ( 0
, 2 0 0 PIPT (Pseudo Independent Particle Truncation) curve p
4 0 0 0 ,
2 shows a sharp peak (positive time delay) around the / 1 , 1 0 0 photon energy of 76eV, whereas the ISST (Intra Sub- 2 2 0 0 0 /
3 Shell truncation) curve shows a sharp dip (negative d 7 5 8 0 8 5 9 0 9 5 4 0 τ time delay, i.e. time advancement) around 77eV of photon energy at θ = 60o. The cumulative effects of 7 0 7 5 8 0 8 5 9 0 9 5 1 0 0 all the dipole transitions provide the detailed spec- 3 0 0 8 0 0 0 o trum of the WES time delay from T4d3/2,1/2,+. At 60 ) 6 0 0 0 2 0 0
s angle, both the real and the imaginary parts of the a amplitude T go through a zero at both level ( 4 0 0 0 4d3/2,1/2,+
0 1 0 0 6
, of truncation with different rates with respect to en-
p
, 2 0 0 0
2 ergy. As a result of this the time delay is positive in
/ 0
1 7 5 8 0 8 5 9 0 9 5 , 0 the PIPT calculation and it is negative in the ISST 2 /
3 t d _ 4 d 3 / 2 _ 1 / 2 _ p _ 6 0 _ P I P T calculation. d - 2 0 0 0 t d _ 4 d 3 / 2 _ 1 / 2 _ p _ 6 0 _ I S S T 4 This study is particularly important to understand τ 7 0 7 5 8 0 8 5 9 0 9 5 1 0 0 the photoionization time delay in near threshold re- gion. Figure 1. (Color online) WES time delay for 4d3/2,1/2 with final state spin polarization positive at different photoelectron ejection angle with respect to the polar- References ization of the photon (0o and 60o respectively from top). [1] W. R. Johnson et al. 1979 Phys. Rev. A 20 964. Red line is PIPT calculation and black line is ISST cal- culation. Inset are the zoomed portions of the graph [2] W. R. Johnson et al. 1982 Phys. Rev. A 25 337. where the hump like structure is present. [3] R. Pazourek et al. 2015 Rev. Mod. Phys. 87 765. [4] M. Ossiander et al. 2016 Nature Physics Development in ultrafast laser technology has made doi:10.1038/nphys3941. it possible to resolve the photoionization dynamics [5] A. Kivimaki et al. 2000 Phys. Rev. A 63 012716. in atomic time scale [3] and opens the door to inves- tigate the effect of electron correlations in real time [6] D. A. Keating et al. 2017 J. Phys. B 50 17. [4]. [7] E. P. Wigner 1955 Phys. Rev. 98 145.
1E-mail: [email protected] 2E-mail: [email protected]
62 ISAMP TC-7, 6 8 January, 2018, Tirupati CA007A Husain −
Study of the excited even configuration of Cs VII
Abid Husain*, S. Jabeen, Abdul Wajid
* Department of Physics, Aligarh Muslim University, Aligarh, UP-202002, India
Topic: A. Quantum collisions and Spectroscopy of atoms, molecules, clusters an ions
2 The ground most level P1/2 and first excita- isfactorily. The work has been further extended tion of Cesium VII was reported by V. Kauf- to the incorporate the thirty four levels belong- man and J. Sugar [1] for the first time in 1987. ing to the even parity configuration 5s2nd (n=6, They reported all the nine levels belonging to 7), 5s2ns (n=7, 8) and 5p25d levels as the the ground configuration 5s25p and the first four transitions were lying below1000Å. The ab excited even configurations 5s5p2, 5s25d and initio calculation was performed using cowan’s 5s26s. They reported twenty-eight out of the code [3]. thirty-five levels belonging to the doubly excit- ed odd configurations 5s2nf (n=4,5) 5s26p,5s5p5d,5s6s5p and 5p3 and one of the fur- References ther excited even configuration 5s5p4f have [1] V. Kaufman and J. Sugar, 1987, J. Spt. Spc. Am. B 4, been reported by R. Gayasov and Y.N. Joshi[2] 1924-1926. in 1999. [2] R. Gayasov and Y.N. Joshi, 1999, Phys. Scripta, 60, In the present work we have confirmed pre- 312-320. viously reported energy levels belonging to [3] R.D. Cowan “Theory of atomic structure and spec- 5s25p, 5s5p2 ,5s25d, 5s26s, 5s2nf (n=4,5) 5s26p, tra” University of California Press, Berkeley 1981 5s5p5d, 5s6s5p, 5p3, 5s5p4f configurations sat-
*E-mail [email protected]
63 ISAMP TC-7, 6 8 January, 2018, Tirupati CA008 Gupta − Electron-impact excitation of Xe+ ion and polarization of subsequent emissions
S.Gupta1, Lalita Sharma and Rajesh Srivastava
Indian Institute of Technology Roorkee, Roorkee-247667, Uttrakhand, India
Topic: A- Quantum collisions and spectroscopy of atoms, molecules, clusters and ions.
Study of electron impact excitation of inert However, Dressler et.al.[1] have reported elec- gas atoms has been a topic of fundamental in- tron impact emission cross sections which are terest for a long time. These atoms exhibit derived from the luminescence spectra. Their strong relativistic and spin-orbit interaction ef- emission spectra show in addition to important fects indicated by their fine-structure splitting of Xe atomic lines, few lines from the Xe+ ion. In the different states, making it a highly challeng- their spectra they observed 12 visible 8 near in- ing case for testing different theoretical models. fra-red lines for electron energies ranging from In addition to their basic fundamental interest, 10-70 eV. In order to explain Xe+ ionic lines a electron collision cross sections are important collisional–radiative plasma model incorporat- for analysis of photon emissions from plasmas ing electron impact excitation cross sections for as well as for applications to different gaseous various atomic states of the Xe+ ions are re- discharges [1−3]. Furthermore, cross sections quired. are essential for identifying electron-impact ex- In the present work, Electron impact excita- cited lines in spectra of various astrophysical tion in Xe+ ions has been studied using fully objects including stars and interstellar gas relativistic distorted wave theory. Calculations clouds. During the past few years, a number of are performed to obtain the excitation cross- theoretical and experimental studies of xenon sections and rate-coefficients for the transitions have been carried out to obtain electron excita- from the lower ground state 3p5 (J=3/2) to fine- tion cross sections for various lower and excited structure levels of excited states 5p46s, 5p46p, states [4]. However, very limited efforts have 3p47s, 3p47p, 3p45d and 3p46d. Polarization of been make to study the electron excitation of the radiation following the excitation has been inert gas ions [3-5]. Recently, Dipti and Sri- calculated using the obtained magnetic sub- vastava [5] have reported their extensive relativ- level cross-sections. We have derived the ex- istic distorted wave (RDW) calculations for pressions for polarization of different transitions electron excitation Ar+ ion from its ground state which are obtained in terms of magnetic sub to several excited fine structure excited states level cross sections which we calculated. All the and the polarization studies of their decay by details of calculations along with the results will photon emissions. be presented in the conference. The study of neutral and ionic state of Xenon have important fundamental interest and appli- References cations viz. in ion thrusters for space propulsion [1] Dressler et al. 2006 J.Appl. Phys. 99 113304 in which the propellant is accelerated by an [2] Dressler et al. 2006 J.Appl. Phys. 99 113305 electric-Hall effect and use the electron to ion- [3] Dressler et al. 2009 J.Phys. D: Appl. Phys 42 ize the propellant which efficiently accelerate 185203 the ions to produce thrust. These thrusters are [4] Lin C C et al. 1998 Phys. Rev. A 58 4603 alternative to chemical propulsion system of [5] R. Srivastava et al. 2016 J Quant Spectrosc Radiat spacecraft. There are number of reports on the Transf 176 12-23 theoretical and experimental electron impact [6] R. Srivastava et al. 2011 Eur. Phys. J. D 62 399- excitation cross sections of neutral Xe atoms [1- 403 3, 6-7] and these data have been utilized to [7] R. Srivastava et al. 2009 J. Phys.: Conf. Ser. 185 012042 characterize various Xe imbedded plasma [3].
1 E-mail: [email protected]
64 ISAMP TC-7, 6 8 January, 2018, Tirupati CA009B Mandal − Wigner-Eisenbud-Smith time delay in photoionization of n f subshell: angle and spin resolved study
1 †,#2 A. Mandal∗ and P. C. Deshmukh
∗ Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India † Department of Physics, Indian Institute of Technology Tirupati, Tirupati, 517506, India # Department of Physics, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
Topic: A, B
Time domain studies of light-matter interac- pends on the angle of emission with respect to the tions covers a variety of research with different photon polarization is very much specific to the focii, extending from astrophysical to biological channels and energies under inspection. Wigner- relevance to foundational aspects of quantum the- Eisenbud-Smith (WES) [3] time delay in single pho- ory [1,2]. It has been realized that photoioniza- ton, dipole photoionization from np and nd subshells tion time delay is angle dependent in general [4]. have been studied earlier [4,5]. In the present work we study WES time delay in photoionization from 2 0 0 0 2 0 the spin-orbit split 4 f states. Following the formal- 4 f 5 / 2 ism of [4,5,6] we compute the WES time delay for 1 0 1 5 0 0 all possible channels from 4 f orbital of atomic Hg. )
s 0 The initial state angular momentum projection and
a
( 1 0 0 0 o 0 final state spin averaged results are shown in Fig. 1. S o E - 1 0 3 0 o W H g 6 0 The interference between different channels pro- τ 5 0 0 o 9 0 duces an angle dependence of the WES time delay - 2 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 which become particularly interesting in the neigh- 0 borhood of 160eV. The angle-dependence is maxi-
1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 mum at about the same energy ( 160 eV) because the p h o t o n e n e r g y ( e V ) 4 f photoionization cross section undergoes a local minimum due to the competition between the oscil- lator strengths in the 4 f εg and 4 f εd channels. 1 2 0 → → o 1 0 0 0 Considering the fact that the local cross-section 4 f 3 0 o minimum is not a Cooper minimum, this study would 8 0 7 / 2 6 0 o o be of significant importance in the investigations on ) 6 0 9 0 s photoionization dynamics. a
( 4 0
S
E 2 0 W
τ References 0 - 2 0 H g [1] R. Pazourek et al. 2015 Rev. Mod. Phys. 87 765 - 4 0 [2] M. Schultze et al. 2010 Science 328 1658 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 p h o t o n e n e r g y ( e V ) [3] E. P. Wigner 1955 Phys. Rev. 98 145 Figure 1. (Color online) WES time delay for 4 f5/2 and [4] A. Kheifets et al. 2016 Phys. Rev. A 94 013423 4 f . 7/2 [5] A. Mandal et al. 2017 Phys. Rev. A, in press How exactly the photoionization time delay de- [6] W. R. Johnson et al. 1979 Phys. Rev. A 20 964
1E-mail: [email protected] 2E-mail: [email protected]
65 ISAMP TC-7, 6 8 January, 2018, Tirupati CA010 Dora − Potential energy curves of the higher lying resonances in electron-CO scattering
1 2 Amar Dora∗ and Jonathan Tennyson†
∗ Department of Chemistry, North Orissa University, Baripada - 751 003, Odisha, India † Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
Topic: A
Electron collision with molecules and the sub- using R-matrix theory and also have calculated sequent processes are of practical use in many the bound parts of the anion potential energy areas of technology. Detailed study of these curves using MRCI level of theory. At the con- processes at the molecular level are therefore of ference we will present these results (see Figure prime importance in their modelling and opti- 1) and discuss about the parentage of these res- mization. In the case of electron collision with onances. These results will be significant in view carbon monoxide, which is the second most com- of the controversy surrounding characterizations mon molecule in the Universe after hydrogen, by experimentalists. there have been several such studies by both ex- 25 perimentalists and theoreticians. Most of the 1Σ+ 1Σ- past studies have concentrated only on the low- 1∆ 1Π 2 20 3 + est lying Π shape resonance which is at about Σ 3Σ- 1.6 eV. In the recent years, however, there has 3∆ 3Π been some experimental studies [1-5] by different 15 1 2Σ+ 2 2Σ+ 3 2Σ+ groups at higher collision energies, while almost 1 2∆ none exist on the theoretical side. These studies Energy (eV) 10 1 2Π which measure the ion yield cross sections clearly show the presence of several resonances in the 9 5 to 12 eV region. However, the characterization 0 of these high lying resonances based on the veloc- 1.7 1.8 1.9 2 2.1 2.2 2.3 ity time sliced imaging, the technique which all R (bohr) these groups used, has proved controversial with Figure 1. Resonance positions and target CASSCF claims and counter-claims, and calling for high energies as a function of inter-nuclear distance us- level theoretical calculations [5]. ing cc-pV6Z basis set.
We have been pursuing to study the dissocia- tion dynamics of the e+CO system theoretically. References Recently, in our first attempt [6] to study the high lying resonances using the R-matrix method [1] P. Nag and D. Nandi, 2015, Phys. Chem. Chem. with a smaller basis set of cc-pVTZ we have had Phys. 17 7130 2 + partial success where we found only one Σ Fes- [2] S. X. Tian at al., 2013, Phys. Rev. A 88 012708 hbach resonance at 12.9 eV having very narrow width in addition to the lowest 2Π shape reso- [3] P. Nag and D. Nandi, 2015, Phys. Rev. A 91 056701 nance. In our newer fixed-nuclei R-matrix cal- culations at the equilibrium bond length of CO [4] S. X. Tian and Y. Luo, 2015, Phys. Rev. A 91 using a very large basis set cc-pV6Z we found 056702 three 2Σ+ resonances at 10.1, 10.38 and 11.1 [5] K. Gope, V. Tadsare, V. S. Prabhudesai, N. J. eV and a 2∆ resonance at 13.3 eV along with Mason, and E. Krishnakumar, 2016, Eur. Phys. the lowest 2Π resonance at 1.9 eV. We have now J. D 70 134 computed the positions and widths of these reso- [6] A. Dora, J. Tennyson and K. Chakrabarti, 2016, nances as a function of the inter-nuclear distance Eur. Phys. J. D 70 197
1E-mail: [email protected] 2E-mail: [email protected]
66 ISAMP TC-7, 6 8 January, 2018, Tirupati CA011 Sharma − Orientation effects in ionisation of CO by proton and ion impact
1 Bhas Bapat∗, Deepak Sharma∗ , Ajit Kumar†, Pragya Bhatt‡ and C P Safvan‡
∗ Indian Institute of Science Education and Research, Pune 411008 † Dept. of Physics, Jamia Milia Islamia, New Delhi 110025 ‡Inter University Accelerator Centre, New Delhi 110067
Topic: A
Multiple ionization of the molecules depends metry effect is observed together with anisotropy on the orientation of the molecules with the beam and both the effects increases with degree of ion- direction. Usually target molecules are ran- ization. Model calculation shows that for a fixed domly oriented in space, so experimental mea- degree of ionization orientation effect should de- surement of this dependence is not straightfor- crease with increase in projectile energy as theo- ward. For the special case of fragmentation (dis- retically calculated by Kaliman et al [5]. sociative double or higher ionisation) of a di- 1.4 atomic molecule, it is possible to establish this CO2+ CO3+ 1.2 CO4+ angle from the coincidence measurement of the sin(θ)
angular distribution of the two separated ions. 1 ] t i n u
Several workers have looked into this aspect and .
b 0.8 r a [
many trends have been observed for homonuclear y t i
s 0.6 n e
as well as heteronuclear molecules, mostly N2 t n I and CO [1,2,3,4]. Specifically, no studies have 0.4
made a distinction between the effects of align- 0.2
ment – which merely indicates a propensity to an 0 axis, and orientation – which indicates a specific 0 30 60 90 120 150 180 Angle [deg] pointing towards one or the other direction of an axis. We have investigated the fragmentation of Figure 1. Multiple ionization of CO in collision CO molecule subject to collisions with protons with proton at 50 keV energy and highly charged ions. Angular distributions of the fragments are derived from the coincidence Orientation effects also dependes on the in- n1+ n2+ momentum spectra of C and O ions re- teraction strength of the projectile, defined by n+ sulting from the dissociation of CO ions with Sommerfeld parameter k = q/v. For the high n1 + n2 = n. The orientation dependence of the interaction strength, more electron may be re- ionisation cross-section is parametrised by the fit moved for a given trajectory but at the same time to the observed angular distribution of fragment the contributions from large impact parameters ions become significant. However, as the impact pa- rameter becomes significantly large than the size N(θ) = N [1 + β P (cos θ) + β P (cos θ)] sin θ 0 1 1 2 2 of the molecule, the orientation effect becomes weaker. Collisions with Ar7+ and Xe9+ impact In this function β1 represents the asymmetry of the cross-section in the forward and backward show only a weak dependence at even higher de- hemispheres w.r.t. the projectile, and is a mea- gree of ionisation. sure of the orientation effect in heteronuclear molecules, while β2 is a measure of anisotropy, References applicable to both heteronuclear and homonu- [1] Wohrer, K. and Watson, R. L. 1993 Phys. Rev. A clear molecules. For proton impact in the en- 48 4784 ergy range 25–200 keV we find strong orientation dependence of the ionisation cross-sections, espe- [2] C Caraby et al 1997 Phys. Rev. A 55 2450 cially at lower incident energies and higher degree [3] U Werner et al 1997 Phys. Rev. Lett. 79 1662 of target ionisation. In Figure 1, experimental [4] B Siegmann et al 2001 Phys. Rev. A 65 010704 result for multiple ionization of CO in collision with proton at 50 keV energy is shown. Asym- [5] Z Kaliman et al 2001 Phys. Rev. A 65 012708 1E-mail: [email protected]
67 ISAMP TC-7, 6 8 January, 2018, Tirupati CA012 Montanari − The IAEA database for stopping power, trends in the energy loss experimental research
C. C. Montanari* 1, P. Dimitriou† 2
* Instituto de Astronomía y Física del Espacio, CONICET and Universidad de Buenos Aires, Argentina. *Facultad de Ciencias Exactas y Naturales, Univerisdad de Buenos Aires, Buenos Aires, Argentina. †Division of Physical and Chemical Sciences, International Atomic Energy Agency, Vienna, Austria.
A: An overview of the state of art of the energy loss of ions in matter is presented based on our work for the stopping power database of the International Atomic Energy Agency. Our goal is to identify areas of interest, trends, and emerging data needs. We address the interest in new materials such as polymers, oxides or silicon compounds of technological interest, and the necessity of theoretical developments to describe the energy loss of ions in these targets.
The aim of this work is to present a re- The stopping powers are relevant to a wide view of the stopping power of ions in matter, range of applications such as ion beam analysis, focused on the experimental data published deposition ranges (perhaps the most demanding since 2000. We based on the stopping power data is on water and biological targets due to the database of the International Atomic Energy application to hadron therapy), ion implantation Agency (IAEA) [1]. This exhaustive collection (i.e. for doping metal oxide semiconductors to of experimental data, graphs, programs and the industry of electronic devices and hard comparisons, is the legacy of Helmut Paul glasses), and radiation damage (the relation ([1,2] and references therein) who made it ac- with the electronic stopping power is empiri- cessible to the global scientific community, and cally clear, with different evaluations such as has been extensively employed in theoretical the losses of functional groups in complex and experimental research during the last 25 molecules [6]. years. This collection comprises compilations of experimental measurements made in different 2010-2016 Helsinki laboratories worldwide and covers the period Upsala Jyvaskyla since the early measurements in the 30s and 40s Varsovia Linz Zagreb up to the present. The values of more than 850 Catania Oak Ridge Kyoto references are included. Argelia New Delhi
Kurukshitra
Period: 2001-2016 Last period: 103 exp in compounds 55 exp in atomic targets Stopping Power measurements
100 San Pablo Porto Alegre
80 Valparaiso IThemba, SA
2005-2008 Bariloche 2009-2012 2001-2004 2013-2016 60
40 Figure 2. Laboratories around the world with meas- 20 Compounds Atoms urements of electronic energy loss since 2010. Number of ion-atom systems measured systems ion-atom Number of
0 4 year period References [1] https://www-nds.iaea.org/stopping/ Figure 1. Number of ion-target systems measured [2] Paul (2013), AIP Conf. Proc. 1525, 295. since 2001 as function of time. Compounds duplicate [3] Montanari et al (2017), Nucl. Instr. Meth. Phys. Res. the atomic targets. Data from IAEA database [1]. B 408, 50. [4] Nandi et al (2013), Phys. Rev. Lett. 110, 163203. The field of stopping powers in matter is [5] Roth et al (2017), Phys. Rev. Lett. 118, 103401. evolving with new trends in materials of inter- [5] Miksova et al (2016), Nucl. Instr. Meth. Phys. Res. B est, including oxides, polymers, and biological 371, 81. targets [3-5]. [6] Kusumoto et al (2016)., Rad. Measurements 87, 35.
1 E-mail: [email protected] 2 E-mail: [email protected]
68 ISAMP TC-7, 6 8 January, 2018, Tirupati CA013 Montanari − Energy loss of low energy protons and antiprotons in metals
C. C. Montanari 1, J. E. Miraglia 2
Instituto de Astronomía y Física del Espacio, CONICET and Universidad de Buenos Aires, Argentina Facultad de Ciencias Exactas y Naturales, Univerisdad de Buenos Aires, Buenos Aires, Argentina
Topic A: We propose a non-perturbative approximation to the electronic stopping power based on the central screened potential of a projectile moving in a free electron gas, by Nagy and Apagyi. We calculate the energy loss of protons and antiprotons in ten solid targets: Cr, C, Ni, Be, Ti, Si, Al, Ge, Pb, Li and Rb. Our formalism is valid for low impact velocities, where plasmon excitations are not important. We extend the energy loss calculations to intermediate and high energies by using the Lindhard dielectric formalism (including plasmons) and the SLPA model to include the inner-shell contri- bution.
In the last decade, the stopping power has 2, we display similar results but for proton im- had a revival due to the requirement of more pact. As the targets Si, Al and Ge have very accurate experimental data, and to the possibili- similar rs, the value of Q is expected to be very ties and precision of the up to date techniques similar for the three targets. This is verified ex- [1]. Perhaps, the most challenging ones are the perimentally and in our theoretical description. low-energy antiproton experiments at CERN and the future prospects of the Facility for Anti- proton and Ion Research at Darmstadt [2]. The low energy behavior of the stopping power has attracted many of the experimental efforts in the last years [3,4]. The accuracy of the new experimental techniques and the neces- sity of full theoretical data, lead us to wonder on the highest theoretical precision to describe the low-energy new experimental values.
Figure 2. The friction for low energy protons in solids. Curves, the present model. Symbols, experimental data in [5].
The combination of this model for low im- pact energies and perturbative ones (but includ- ing plasmons) for higher energies proved to de- scribe the stopping power in a large energy range [5] Figure 1. The friction for low energy antiprotons in solids. Curves, the present model. Symbols, experi- References mental data in [5]. [1] Montanari et al (2017), Nucl. Instr. Meth. Phys. Res. B 408, 50. We present here a non-perturbative binary [2] FAIR, Facility for Antiproton and Ion Research, collisional model to describe the electronic http://www.fair-center.eu/. stopping power, dS/dx, of heavy charged pro- [3] Celedon et al (2015), Nucl. Instr. Meth. Phys. Res. B jectiles in a free electron gas. The friction 360, 103. Q=(dS/dx)/v is a sensitive parameter at low im- [4] Roth et al (2017), Phys Rev Lett 118, 103401. pact velocities, which is approximately constant [5] Montanari et al (2017), Phys Rev A 96, 012707. in an homogeneous free electron gas. In Fig. 1 we display friction for antiprotons in three different solids, Al, Si and C. In figure
1 E-mail: [email protected] 2 E-mail: [email protected]
69 ISAMP TC-7, 6 8 January, 2018, Tirupati CA014 Bhavsar −
Electron interaction scattering cross sections of Astromolecules
Rakesh Bhavsar 1, Yogesh Thakar 2, Chetan Limbachiya 3
1, 2 M. N. College, Visnagar – 384315, Gujarat, India 3The M.S.University of Baroda, Vadodara-390001, Gujarat, India
Synopsis: Total Cross sections calculations for electron interaction with astromolecule is presented here.
Topic:A
The discovery and study of astromolecules We report a theoretical total scattering have gained importance due to the cross sections of electron interaction with fundamental interest in basic science as well Astro- molecules in the energy range from as for the investigation of possible extra- threshold to 5 keV. Here ‘Spherical Complex terrestrial life and such studies have been Optical Potential’ (SCOP) [3] formalism made possible and facilitated by the advent employed to evaluate Qel, Qinel, and Qtotal of modern space activities. The molecules and used our semi-empirical, ‘Complex found in the inter-stellar clouds, various Spherical Potential – ionization contribution’ cometary and planetary environments as well (CSP-ic) method to derive Qion and ΣQexc as those which are detected over moons of [4]. Results are compared with experimental the planets are being explored [1, 2] and theoretical data wherever availabl
References
[1] Gautier, Nathalie Carrasco , Arnaud Buch , Cyril Szopa , Ella Sciamma-O’Brien, Guy Cernogora, , ICARUS Nitrile gas chemistry in Titan’s atmosphere 213, 625–635 (2011)
[2] N Carrasco et al., Volatile products controlling Titan’s tholins production. ICARUS, 219, 230-240 (2012)
[3] Mohit Swadia, Rakesh Bhavsar, Yogesh Thakar, Minaxi Vinodkumar & Chetan Limbachiya Molecular Physics, 115, 2521-2527 (2017)
[4] M. Swadia, Y. Thakar, M. Vinodkumar, and C. Limbachiya, Eur. Phys. J. D. 71, 85(2017).
1 E-mail: [email protected] 2 E-mail: [email protected] 3 E-mail: [email protected]
70 ISAMP TC-7, 6 8 January, 2018, Tirupati CA015 Thakar −
Electron interaction scattering cross sections of Biologically relevant molecule
Yogesh Thakar 1, Rakesh Bhavsar 2,Chetan Limbachiya 3
1, 2 M. N. College, Visnagar – 384315, Gujarat, India 3The M.S.University of Baroda, Vadodara-390001, Gujarat, India
Synopsis: Total Cross sections calculations for electron interaction with Biologically relevant molecule is presented here.
Topic: A
or ionization. It has been proved experimentally The high energy ionizing radiation like X- [2,3] that such low energy electrons can induce rays, γ-rays and ±β-particles is widely used significant amount of single and double stand in medical diagnostic and cancer therapy. breaks in the DNA. Since that discovery, many Simplifying, during interaction of such high experimental and theoretical works concerning energy particles with living cells two low- and intermediate-energy electron complex processes are very important. In the interaction with DNA and its building blocks, as first stage the high energy primary radiation well as simple molecular analogs of its can induce direct damage to the cell. During constituents have been done [4-6] that process variety of secondary species, including low energy electrons (LEE) are We report Various Theoretical total produced. In the second process secondary scattering cross sections for interaction of species can react with their environment, electron with Biological relevant molecule. what can lead to the further damage of the Here we deploy SCOP [7] for calculations of cell. The number of these low energy (0−20 Elastic, Inelastic, and total Cross Sections eV) secondary electrons is 4 Using CSP-iC formalism [8] ionization cross significant,4×10 electrons per 1 MeV of sections are calculated. Excitation cross radiation [1] sections are byproduct of above calculations. Such LEE can react with molecular Results are compared with experimental and environment in different way and some of the theoretical data wherever available allowed pathways can lead to chemical reactions for example via dissociative electron attachment
References: [1]. V. Cobut, Y. Fongillo, J.P. Patau, T. Goulet, M.J. Frases, J.P.Jay-Gerin Radiat. Phys.Chem. 51,229(1998) [2. B. Boudaiffa, P. Cloutier, D. Hunting, M.A. Huels, L.Sanche, Science 287, 1658 (2000) [3] B. Boudaiffa, D.J. Hunting, P. Cloutier, M.A. Huels, L.Sanche, Int. J. Radiat. Biol.76, 1209 (2000) [4] L. Sanche, Mass Spectrom. Rev.21, 349 (2002) [5] L. Sanche, Eur. Phys. J. D 35, 367 (2005) [6] C. Winstead, V. McKoy, Radiat. Phys. Chem.77, 1258(2008) Eur. Phys. J. D(2012) 66: 54 [7] Mohit Swadia, Rakesh Bhavsar, Yogesh Thakar, Minaxi Vinodkumar &Chetan Limbachiya, Molecular Physics, 115, 2521-2527 (2017) [8] M. Swadia, Y. Thakar, M. Vinodkumar, and C. Limbachiya, Eur. Phys. J. D.71,85(2017)
1 E-mail: [email protected] 2 E-mail: [email protected] 3 E-mail: [email protected]
71 ISAMP TC-7, 6 8 January, 2018, Tirupati CA016 Prajapati − Electron Induced chemistry of Chlorobenzene
, 1 2 3 4 Dineshkumar Prajapati∗ † , Hitesh Yadav† , Minaxi Vinodkumar‡ , P C Vinodkumar†
∗ Shree M R Arts & Science College, Rajpipla - 393145, India † Department of Physics, Sardar Patel University, Vallabh Vidyanagar - 388120, India ‡ V. P. & R. P. T. P. Science College, Vallabh Vidyanagar - 388120, India
Topic: A
Electron impact studies with organic targets As a sample result we report here DCS data gained prominence after the study, that sec- of e-C6H5Cl scattering at 20 eV in Figure 1. The ondary electrons produced by energetic radia- present data finds overall good agreement with tions are responsible for single and double strand the dataset of Barbosa et al.[6]. breaks in DNA. Moreover systematic and de- tailed knowledge of cross sections resulting from
electron collisions with simple organic systems 1000
Present
Barbosa exp.
can help us to understand the behaviour of more Barbosa_IAM-SCAR
Barbosa_SMCPP
complex biomolecules. 100
20eV /sr) A detailed theoretical study is carried out 2 cm
10
for electron interactions with chlorobenzene -16 (C6H5Cl) with impact energies ranging from
1 0.01 to 5000 eV. Owing to the wide energy range (10 DCS we have been able to investigate variety of pro-
cesses and report data on dissociative electron 0.1 attachment (DEA) through resonances, vertical 0 20 40 60 80 100 120 140 160 180
(degree) electronic excitation energies, differential, mo- mentum transfer, ionization and total cross sec- Figure 1. Differential Cross Section of chloroben- tions (TCS) as well as scattering rate coefficients. zene at 20eV In order to compute TCS we have employed ab initio R-matrix method (0.01 to 20 eV) [1,2] and Minaxi Vinodkumar acknowledge DST- the spherical complex optical potential (SCOP) SERB, New Delhi for the Major research project method (20 to 5000 eV) [3,4]. The R-matrix [EMR/2016/000470] for financial support under calculations were performed using close coupling which part of this work is carried out. approximation employing a static exchange plus polarization (SEP) model. The target proper- ties reported using quantum chemistry codes are References in good agreement with earlier reported data as [1] M.Vinodkumar et al. 2015 RSC Adv. 5 24564 shown in Table 1. [2] M. Vinodkumar et al. 2016 Phys. Rev. A 93 Table 1. Target Properties of Chlorobenzene 012702 Target property (unit) Present Other[5] [3] H. Yadav et al. 2017 Molecular Physics 115-8 Ground State (Hartree) -688.64 -689.99 952-961 [4] M.Vinodkumar et al. 2015 RSC Adv. 5 69466 Ionization Potential (eV) 9.200 9.080 [5] http://cccbdb.nist.gov Dipole Moment (Debye) 1.689 1.690 [6] Barbosa et al. 2016 J. Chem. Phys. 145 084311
1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 4E-mail: [email protected]
72 ISAMP TC-7, 6 8 January, 2018, Tirupati CA017 KrishnaKumar −
Optical breath gas sensing using UV-VUV absorption spectroscopy
Sunanda Krishna Kumar1, B.N. Rajasekhar2 and Asim Kumar Das Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
Topic A. Quantum collisions and spectroscopy of atoms molecules, clusters and ions.
Volatile organic compounds (VOCs) release and analysis linked to medical condition is a new fron- tier in medical diagnostics [1]. This technique finds application in Breathe analysis, an inexpen- sive, rapid and non-invasive diagnostic method, useful in a variety of clinical applications. In the present work we are proposing to use UV-VUV spectroscopy to study the VOC composition from exhaled gas involved in a respiration process as an analytical tool for two gas detection. Few sensor development projects do exist for measuring hu- midity in breathing condition [2] and breath sen-
sor to detect NH3 [3]. However an optical sensor for detecting two VOC emissions (Carbon disul-
fide (CS2) and pentane (C5H12)) contained in breath sample of a subject suffering from Schi- Figure 1. Excited state energy comparison of atmos- pheric molecules, CS and C H zophrenia [2] does not exist till date. In this paper 2 5 12
we present the spectroscopic method required to Details of computed excited state energies, identify a spectral region free from spectral interfe- excited state ordering, simulated & experimental rence among these molecules to develop optical spectra required for unambiguous selection of sensing method for two molecule gas detection. spectral region for two optical molecular gas sens- For this purpose vertical excited state ener- ing will be presented in this paper. gies have been computed and plotted for atmos-
pheric molecules, CS and C H as shown in fig.1. 2 5 12 References: It is clear from the excited state data that atmos- 1. Julian W. Gardner, Sensors 2016, 16, 947. pheric gases absorb in different characteristic wa- 2. S.Morisawa et.al. Proc. IEEE Sensors, 2004, pp.1277. velength regions and carbon disulfide & pentane 3. R. Lewicki et.al. Optical Society of America, 2009, also have specific absorptions. From the excited pg. CMS6. state information it appears that there is no absorp- 4. M Phillips et.al. 1993, J Clin Pathol 46 861. tion of N and CO above 170nm; O , H O and CO 2 2 2 and CO2 have little absorption in the energy region of 185 -220 nm and almost zero absorption beyond
220nm up to 250 nm (CO2 and CO have very little absorption; in comparison with molecules under consideration.
1E-mail: [email protected] 2E-mail: [email protected]
73 ISAMP TC-7, 6 8 January, 2018, Tirupati CA018 Montanari − Fully relativistic structure calculations of heavy targets for inelastic collisions
Mendez, A. M. P. 1, Mitnik, D. M., Montanari, C. C.
Instituto de Astronom´ıay F´ısicadel Espacio, CONICET–UBA, Buenos Aires, Argentina
Topic: A. Fully relativistic structure calculations for Ta (Z=73), Pt (Z=78), Th (Z=90) and U (Z=92) are presented here. The description of these atoms requires the solution of the relativistic Dirac equation. We used the hullac suite of codes to compute their atomic structure. The results obtained for the energies of the bound orbitals are compared with experimental ones, obtaining a good overall agreement. The method uses the parametric potential model that allows to obtain a unique potential. This enable us to represent both bound and continuum states in the same footing, which is of great interest in several inelastic collisional calculations, such as stopping, straggling and multiple ionization.
The description of heavy atoms requires the the more external shells are accounted for the solution of the relativistic Dirac equation. To structure differences between the atoms (com- this end, we used the hullac code package [1], puted) and the solids (experiments). Previous which allows one to obtain accurate relativis- structure calculations for other atomic systems tic one-electron orbitals and multiconfiguration showed accurate description of relativistic targets bound states and energies. The calculations are in various inelastic collisions processes, particu- based on first-order perturbation theory with a larly energy–loss and straggling [5]. Further col- central field, including the contribution from the lisional calculations for these atoms are presented Breit interaction and quantum electrodynamics in the conference by one of the authors. corrections. The detailed energy levels are com- 4 puted using the relac code [2], which uses the 10 3 parametric potential model. This model consists 10 2 in minimizing the first–order relativistic energy 10 1 of a given set of configurations for a paramet- 10 0 ric analytical function for the screening charge 10 U Pt -1 distribution. Although this code was written for 10 1s 2s 3s 4s 5s 6s 7s 4f- 5f- 2p- 3p- 3d- 4p- 4d- 5p- 5d- 6p- 6d- 4f+ 5f+ 2p+ 3p+ 3d+ 4p+ 4d+ 5p+ 5d+ 6p+ calculations of heavy ionized atoms, it can be 6d+ 4 successfully employed in other atomic systems, 10 3 such as the ones presented here. 10
Binding energies (ryd) 2 First, we calculated the atomic structure with 10 1 nonrelativistic and semirelativistic approaches 10 0 Th 10 using the autostructure code [3]. We com- Ta -1 pared the computed binding energies of the 10 7s 6s 4s 5s 3s 1s 2s 4f- 6p- 6d- 4p- 4d- 5p- 5d- 3p- 3d- 2p- 4f+ 6p+ 6d+ 4p+ 4d+ 5p+ 5d+ 3p+ 3d+ bound orbitals with the experimental values in 2p+ solid compiled by Williams [4]. The nonrelativis- Figure 1. Theoretical and experimental binding tic calculations showed large discrepancies with energies for Pt, U, Ta, and Th. the experimental results, which probed the neces- sity of a relativistic approach. Then, the semirel- References ativistic method was tested, allowing to obtain [1] A. Bar-Shalom, M. Klapisch, and J. Oreg, J. better agreement with the experimental binding Quant. Spectrosc. Radiat. Transf. 71, 169 (2001). energies. However, the large errors found for the [2] M. Klapisch, J. L. Schwob, B. S. Frankel, and most tightly bound inner orbitals evidenced the J. Oreg, J. Opt. Soc. Am. 67, 148 (1977); M. need of fully relativistic calculations. Klapisch, Comput. Phys. Commun. 2, 239 (1971). The binding energies obtained for Ta, Pt, Th [3] N. R. Badnell, J. Phys. B 30, 1 (1997); M. S. and U using the fully relativistic method are Pindzola and N. R. Badnell, Phys. Rev. A 42, shown with up–filled triangles in Fig. 1. The 6526 (1990). figure also includes the experimental bound en- [4] http://xdb.lbl.gov/Section1/Sec 1-1.html ergies (hollow circles) [4]. The values computed [5] C. C. Montanari, C. D. Archubi, D. M. Mitnik and for the inner orbitals agree with the experimental J. E. Miraglia, Phys. Rev. A 79, 032903 (2009); ones in about 2%. The discrepancies found with Phys. Rev. A 80, 012901 (2009). 1E-mail: [email protected]
74 ISAMP TC-7, 6 8 January, 2018, Tirupati CA019 KumarManoj − Kinetic energy release distribution in electron dissociative ionization of CO2
Manoj Kumar!, R. Singh and S. Pal
Department of Physics, M.M.H. College, Ghaziabad-201001 (UP)
Topic: (A) Quantum collision and Spectroscopy of atoms, molecules, clusters, and ions.
There has been increasing interest in dissocia- as input has been employed to evaluate the ioniza- tive/ multiple ionization of atoms and molecules by tion cross sections corresponding to the formation charged particles. Because of coulomb repulsion of doubly charged ions. The calculated electron io- between two positive charged ions are unstable and nization cross section profile then used to compute dissociate into ionic fragments with a concomitant the kinetic energy release distribution. kinetic energy release. Therefore, it is necessary to On the other hand the angular distribution understand the mechanism of the kinetic energy cross sections for the ion formation is obtained as release before the excitation and dissociation dy- 푑휎 휎 훽 namics of doubly charged molecular cations can be = 1 + 1 + 3푝푐표푠2휃 푑훺 4휋 4 explained. Experimental studies may provide in- formation such as the shape of the potential surface where σ, β, θ and p are ionization cross section, of the precursor-ion states, and the energy partition- asymmetric parameter, angular distribution and de- ing among the internal degrees of freedom of the gree of polarization, respectively. The trend of the ionic fragments and their kinetic energies in the present results reveal qualitative agreement as for framework of direct double photo-ionization of mo- the photo-ionization profiles. lecules and subsequent dissociation [1]. In the present work, we have evaluated kinet- References ic energy released distribution of ionic fragments (C+ and O+) produced upon dissociative double io- [1] T. Masuoka et al. 2000, J. Chem.Phys. 113 6634. nization of CO2 by electron impact with energies varying from ionization threshold to 100 eV. A [2] R.Kumar, 2013 Rapid Commun. Mass Spec- semi-empirical formulation [2], based on the photo trom. 27 223 and references therein. ionization cross section/ the oscillator strength data
! E-mail: [email protected]
75 ISAMP TC-7, 6 8 January, 2018, Tirupati CA020 Das − VUV Spectroscopy of Diethyl Carbonate
Asim Kumar Das1, Sunanda Krishnakumar and B. N. Rajasekhar2
Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai - 400085.
Topic: A. Quantum collisions and spectroscopy of atoms, molecules, clusters and ions
Diethyl carbonate (OC(OCH2CH3)2) is one in nature. Spectrum shown in Fig.1 contains of the green solvents widely used as electrolyte two broad features with overlying vibronic fea- in lithium batteries and molecular modeling is a tures. The first excited state of finite oscillator powerful tool for a microscopic understanding strength at 8 eV corresponds to transition from of interactions, processes and phenomena in- HOMO (orbital 32 of symmetry b1) to LUMO volving them [1]. Diethyl carbonate, a carbon- (orbital 33 of symmetry a1). The computational ate ester, is a clear liquid at room temperature studies predict strong interaction between the with a low flash point. It is used in the produc- valence and Rydberg states below 9 eV. tion of polycarbonates and proposed as a fuel additive [2]. It is used as a solvent in medicinal applications e.g. erythromycin intramuscular injections [3]. In spite of its usefulness as a sol- vent in many important application areas, processes and phenomena involving diethyl carbonate is far from complete as the spectro- scopic data available on this molecule is sparse. Therefore, experiments have been carried out to obtain electronic excited state information on this molecule in gas phase. VUV photoabsorp- tion spectrum of diethyl carbonate (DEC) in gas phase is recorded using monochromatic syn- chrotron radiation from Photophysics beamline
[4] at Indus-1 synchrotron radiation source at Figure 1. VUV absorption spectra of DEC recorded RRCAT, Indore in the energy region 7 eV to using synchrotron radiation at Photophysics beamline 11.3 eV as shown in Fig. 1. In addition, gas phase infrared spectroscopy has been carried The experimental results and analysis of the out using FTIR in the energy region 4000-500 VUV absorption spectrum will be presented -1 cm . The results from these studies shall add along with computational results performed us- valuable information of the energetic of excited ing GAMESS (USA) [5]. states, energy ordering, assignment and nature of excited states etc. References In addition, geometry optimization and vi- brational frequency calculations of neutral and [1]Sudip Das et al. 2017, Curr. Opin. Green Sustain. Chem. 5, 37 ionized DEC have been carried out using den- [2]K Shukla et al. 2016, RSC Adv. 6, 32624 sity functional theory (DFT) method for a vari- [3]William H. Brown, Organic Chemistry 6th Ed. ety of basis sets and correlation functional. The [4] N C Das et al. 2003, J. Opt. (India) 32, 169 ground state equilibrium structure of DEC be- [5]M W Schmidt et al.1993, J. Comput. Chem. 14, longs to C2V point group. The vertical and adia- 1347 batic ionization energy obtained from these simulations is 11.52 eV and 11.25 eV respec- tively. Time dependent DFT (TDDFT) calcula- tions have been performed for the analysis of electronic excited singlet and triplet states. Lambda diagnostic analysis suggests that low lying excited states are predominantly Rydberg
1E-mail: [email protected] 2E-mail: [email protected]
76 ISAMP TC-7, 6 8 January, 2018, Tirupati CA021 Bala − Ab initio calculations of spectroscopic parameters of HfH+ and PtH+ Renu Bala 1, H. S. Nataraj 2, Minori Abe 3
1,2 Department of Physics, Indian Institute of Technology Roorkee, Roorkee - 247667, India 3 Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
Topic: A
The polar diatomic molecules are of interest
to experimentalists looking for a non-zero elec- Table 1. The spectroscopic parameters (Re in au 1 tric dipole moment of an electron (eEDM). The and De in eV and the rest in cm− ) and number current best limit on eEDM also comes from the of vibrational states (v) for HfH+ and PtH+ calcu- ultracold molecular experiment on ThO. On the lated at SCF level. other hand, calculating spectroscopic parame- Molecule Re De ωe ωexe Be αe v ters and properties of such molecules containing HfH+ 3.47 6.49 1799 19.8 4.97 0.09 60 heavy atoms is a challenge to theorists because of PtH+ 2.87 7.26 2307 21.9 6.94 0.10 43 their complex electronic structure. As the eEDM hitherto has evaded detection, new systems are being proposed and explored constantly. Two -15089.8 (a) + + 1500 (b) such molecular candidates: PtH , and HfH + + -15090 HfH HfH have been proposed by Meyer et al. [1] and 1000 -15090.2
they have obtained the potential energy curves ) (PECs) for ground- and lower- excited states -1 500
-15090.4 (cm v
using perturbation theory non-relativistically. -E 0
+ -18436.5 v+1 PtH is also studied by Skripnikov et al. [2] for (c) E 2000 (d) Energy (au) + + PtH PtH some spectroscopic constants of a few low ly- -18436.8 1500 ing excited states. Quite recently, low lying Ω 1000 electronic states of PtH and PtH+ have been -18437.1 500 computed by Shen et al. [3] using MRCISD+Q 5 10 15 20 0 10 20 30 40 method. Nuclear distance (au) Vibrational quantum number In this work, we have performed relativistic en- Figure 1. PECs of, (a) HfH+, (c) PtH + and rel- ergy calculations for 1Σ ground state of PtH+ ative vibrational energy spacing (b) HfH+ and (d) and also HfH+ molecular ions at SCF and CCSD PtH+. level of correlation using DIRAC15 program [4]. The cc-pVQZ basis set for H atom and Dyall va- lence basis set, dyall.v4z for Pt and Hf are used in conjunction with Gaussian charge distribution References and C2v point group symmetry. From the calcu- [1] E. R. Meyer et al. 2006 Phys. Rev. A 73 062108 lated PECs, we have obtained the spectroscopic constants and vibrational states using VIBROT [2] L. V. Skripnikov et al. 2009 Phys. Rev. A 80 060501(R) program in MOLCAS [5]. The diatomic con- stants together with the number of vibrational [3] K. Shen et al. 2017 J. Phys. Chem. A 121 3699 states for the two cations calculated at SCF level [4] DIRAC, a relativistic ab initio electronic struc- are tabulated in Table 1. The PECs and rel- ture program, Release DIRAC15 (2015),written ative energy spacing, (E E ) between the by T. Saue, L. Visscher, H. J. Aa. Jensen et al. v+1 − v adjacent vibrational states is shown against the (see http://www.diracprogram.org) vibrational quantum number in Figure 1. The [5] G. Karlstr¨om, et al. MOLCAS: a program pack- detailed results will be presented in the confer- age for computational chemistry, Comput. Mat. ence. Sci. 28, 222 (2003). 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected]
77 ISAMP TC-7, 6 8 January, 2018, Tirupati CA022 Parida − Ultrafast s pectroscopy of p erovskite i nterfaces Manas R. Parida * 1 and Omar F. Mohammed † 2
* Department of Physics, Central University of Rajasthan – 305801, Rajasthan, India † Solar and Photovoltaics Engineering Research Center, Division of Physical Sc iences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955 - 6900, Kingdom of Saudi Arabia
Topic: A
Ultrafast charge transfer (CT), separation (PCBM). When TCNE /PCBM was added suc- (CS) and recombination (CR) at the donor - cessively to the CsPbBr 3 NCs - both doped and acceptor interface, has been proven to be k ey in undoped, resulted a gradual decrease in emis- solar cell performance. 1 How to control these sion inte nsity. It is worth mentioning that such ultrafast processes remains a topic for debate. exciton quenching could also be a consequence Here, we report in situ doping of heterovalent of energy transfer, however, we refute such 3+ Bi ions in colloidal CsPbBr 3 perovskite NCs possibility as there is no spectral overlap be- for the first time by hot injection to precisely tween absorpti on of TCNE and emission of tune their ban d structure and excited state dy- NCs. Our time - resolved data demonstrate clear- namics. 2 Upon excitation with a 370 nm laser ly that the charge transfer at the interface of the pulse, the bleaching maxima, also referred to as NCs can be tuned and assisted by metal doping. ground state bleach (GSB) was observed at 506 More specifically, we found that the doping in- nm and positive absorption bands attributed to creasing the free energy driving force ( - ∆G) the excited - state absorption (ESA) o f the excit- which is the energy difference between the mo- ed charge carriers centered at 465 nm was ob- lecular accepto r and donor moieties and subse- served in both doped and undoped NCs. Fur- quently facilitates the interfacial charge transfer ther, the transient absorption ( TA ) spectra re- process shown in scheme 1 . The novel insights vealed a blue shift in the GSB position to 499 highlighted in this work shed light on the key nm for 0.8% Bi - doped CsPbBr 3 NCs as com- variable components not only the energy differ- pared to the undoped one, wh ich is consistent ence between the molecular acceptor and donor with the ground - state absorption. The spectral moieties and subsequently facilitates the inter- changes in the TA of Bi - doped CsPbBr 3 NCs facial charge transfer process. could be attributed to strong perturbation to the electronic structure that occurs when Bi dopant atoms are introduced in the CsPbBr 3 NCs struc- ture . The emission quenching accompanied by decrease in PL decay lifetime in Bi - doped CsPbBr 3 NCs further substantiated the presence of trap states within the band gap of the host CsPbBr 3 NCs upon doping with Bi. Such traps provide alternative ways for electro nic relaxa- tion and consequently reduce the radiative re- combination. Figure 1 . A schematic diagram of electron transport at Then, we took an important step forward by the perovskite NC - fullerene interface. mapping the tremendous impact of metal dop- ing on charge transfer from the NCs to different References molecular acceptors. W e investigated the steady [1 ] QA Alsulami et al . 2016, Adv. Energy Ma- state absorption and emission properties of the ter. 6 , 1502356 undoped and doped NCs in the presen ce of tet- [2] Manas et al. 2017, JACS , 139 ,731 - 737 racyanoethylene (TCNE) and fullerene
1 E - mail: [email protected]
78 ISAMP TC-7, 6 8 January, 2018, Tirupati CA023 Chakraborty − Absolute dissociative electron attachment cross section measurement studies for difluoromethane
Dipayan Chakraborty 1, Pamir Nag and Dhananjay Nandi 2
Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
Topic: A
Dissociative electron attachment (DEA) pro- unable to comment about the symmetry of the cess is important both in fundamental studies lower energy NIR state. and application point of view. DEA is a two Table 1. Absolute DEA cross sections. step process resulting into an anionic and neutral fragments from parent neutral molecule. DEA to Ion Peak position (eV) Cross section fluromethanes have great applications in plasma 21 2 ( 10− cm ) chemistry, material science and semiconductor × F 1.9 3.141 industries [1]. So far only one theory [2] and one − 11.4 9.745 experimental [3] studies on DEA to CH2F2 are available in the literature. No absolute cross sec- CHF 1.9 1.485 tion data are available. − 11.2 2.7 In the present case DEA to CH2F2 has been stud- ied for 0 to 20 eV incident electron energy range Higher energy NIR states are previously reported and three different fragment ions are observed. theoretically by Modelli et. al[2] where the au- The process can be explained as thors predict the presence of two broad σ∗ res- onances with symmetry b2 and a1 around 10 F− + CH2F eV incident electron energy. In the present case CH F + e− (CH F )−∗ CHF− + HF 2 2 → 2 2 → due to poor electron energy resolution the peaks F2− + CH2 are not separated though their presence are con- firmed. Detail study of the dissociation dynamics From the geometry it is clear that F channel is − will be presented in the conference. a simple bond cleavage whereas, CHF− and F2− channels are associated with the rearrangements in the temporary negative ion (TNI). Absolute cross section of the fragment ions are studied within the above mentioned energy range except for F2− ions due to low count rate. The absolute cross section has been shown in figure. 1 for both F− and CHF− ions and the peak values are tab- ulated in Table. 1. In the excitation function we observed two negative ion resonance (NIR) states around 2 eV and 11 eV incident electron energy. Figure 1. Absolute cross section of (a) F− and (b) Previous experimental study reported the forma- CHF− ions obtained from electron collisions with CH F molecule. tion of F− and CHF− fragment ions only [3]. 2 2 The excitation function for F− and CHF− chan- nels above 6 eV incident electron energy is well agreed with the present report. Recently one References time of flight (TOF) based mass spectrometer with higher mass resolution is developed in our [1] L. G. Christophorou et al. 1996 J. Phys. Chem. group and the experiment is performed. Pres- Ref. Data 25 1341 ence of lower energy NIR state which is likely for [2] A. Modelli et al. 1992 J. Chem. Phys. 96 2061 fluoromethane group, is observed first time for [3] H.-U. Scheunemann et al. 1982 Ber. Bunsenges. CH2F2. Though in the present context we are Phys. Chem. 86 321 1E-mail: [email protected] 2E-mail: [email protected]
79 ISAMP TC-7, 6 8 January, 2018, Tirupati CA024 Rashid − The spectrum of quadruply ionized mercury: Hg V
Aadil Rashid† 1, A. Tauheed† 2
† Department of Physics, Aligarh Muslim University, Aligarh-202002, Uttar Pradesh, India
Topic: A.
The spectrum of mercury was recorded in the tions and relativistic corrections. We are mainly 300-2000Å wavelength region on a 3-m normal interested in the analysis of 5d76p-5d77s and 5d76p- incidence vacuum spectrograph, using a triggered 5d76d transition arrays. The optimization of energy spark source. This spectrograph is equipped with a parameters with the help of known level values holographic grating with 2400 lines/mm (with a have been used to predict the new energy levels. plate factor of 1.385 Å/mm) in the first order. The The analysis is in progress and the latest findings ground state electronic configuration of the ion is will be presented in the conference. 8 8 7 7 5d . The analysis of the (5d + 5d 6s)-5d 6p transi- tion arrays [1] has been studied earlier. In the pre- References sent work, theoretical calculations have been car- 8 7 [1] J.-F. Wyart, A. J. J. Raassen, G. J. van het Hof, ried out for 5d , 5d (6s + 7s + 8s + 6d + 7d + 8d) in and Y. N. Joshi, Phys. Scr. 47, 784–791 (1993). 7 7 the even parity system and 5d (6p + 7p), 5d (5f + [2]https://www.tcd.ie/Physics/people/Cormac.McGu 6 6f) and 5d 6s6p in the odd parity system using inness/Cowan/Code/aphysics.lanl.gov/pub/cowan/ Cowan’s code [2] with superposition of configura-
† 1 [email protected] 2 [email protected]
80 ISAMP TC-7, 6 8 January, 2018, Tirupati CA025 Ganesan − Xe 5s Photoionization near the Second Cooper Minimum using RMCTD
Aarthi Ganesan* 1, Gagan B Pradhan†, Pranawa C Deshmukh$&2
* Department of Physics, CPGS, Jain University, Bangalore- 560011 †Department of Physics, National Institute of Technology, Jamshedpur- 831014, Jharkhand $ Department of Physics, IIT Tirupati, Tirupati – 517506, Andhra Pradesh &Department of Physics, IISER Tirupati, Tirupati – 517507, Andhra Pradesh
Topic: A
Synopsis: The angular distribution asymmetry parameter is calculated using the Relativistic Multi-Configuration Tamm-Dancoff Approximation (RMCTD) for the Xe 5s photoelectrons in the region of the second Cooper min- imum (SCM). The results are compared with those from the RRPA and the RRPA-with-relaxation, and with the experimental data.
Xenon subshell photoionization has been exten- The RMCTD (GM) result, which is the geo- sively studied [1-5]. The photoionization of Xe metric mean of the length and the velocity 5s subshell undergoes a second Cooper mini- forms, is in very good agreement with the ex- mum (SCM) at ~95 eV above the 5s threshold perimental data (see Figure 1). energy. Whitfield et al., [6] have measured the angular distribution of the Xe 5s photoelectrons 2.0 in the SCM region. The measurement has been 1.9 RMCTD (V) done using two different beam lines, the plane 1.8 grating monochromator, PGM, (open circles in 1.7 Figure 1) and the new varied line-spacing plane RMCTD (GM) grating monochromator, VLS-PGM, (closed 1.6
5s RMCTD (R) circles in Figure 1) both with an undulator pho- 1.5 ton source. The deviation of the photoelectron angular 1.4 RRPA distribution asymmetry parameter β from 2.0 1.3 RRPA-R
due to the relativistic effects is further accentu- 1.2 ated in the Cooper minimum [7] region due to 75 100 125 150 175 200 225 Photoelectron energy (eV) fact that the matrix elements of the relativistic subshells go to zero at different energies. The experimental dip of the β parameter reaches a Figure 1. The angular distribution asymmetry pa- value of 1.66 as shown in the figure. rameter of Xe5s photoelectrons using the RRPA [20 Various theoretical calculations are done in ch], the RRPA-R [20 ch] and the RMCTD methods. RMCTD (R) is the length form, RMCTD (V) is the this SCM energy region. The RRPA [4] method velocity form and the RMCTD (GM) is the geomet- that includes most of the important electron cor- ric mean of both the forms. Expt plot [6]. relations measures a larger dip in the β value, ~1.34, compared to the experimental plot. The References RRPA-with-relaxation [2] shows a further dip compared to the unrelaxed RRPA calculation [1] Kutzner M, Radojevic V and Kelly H P 1989 Phys. Rev. A 40 5052 (Figure 1). [2] Johnson W R and Cheng K T 1978 Phys. Rev. In the present work, we have employed also Lett 40 1167 the Relativistic Multi Configuration Tamm- [3] Johnson W R and Lin C D 1979 Phys. Rev. A Dancoff Approximation (RMCTD) [8] to study 20 964 the photoionization of Xenon 5s. Non-RPA cor- [4] Deshmukh P C and Manson S T 1985 Phys. relations are included in the RMCTD by (a) Rev. A 32 3109 mixing the important exited state configurations [5] Fahlman A et al., 1983 Phys. Rev. Lett 50 1114 (b) and by including dipole channels also from [6] Whitfield et al., 2007 J. Phys. B 40 3647 the excited state configurations to the continu- [7] Cooper J W 1962 Phys. Rev. A 47 1841 um, along with the bound-to-bound dipole [8] Radojevic V and Johnson W R 1985 Phys. Rev. A 31 2991 channels to account for additional correlations.
1 E-mail: [email protected] 81 2 E-mail: [email protected] ISAMP TC-7, 6 8 January, 2018, Tirupati CA026 Singh − Positron collision dynamics for C2-C3 hydrocarbons
1 2 Suvam Singh∗ , Pankaj Verma, Vishwanath Singh, Bobby Antony∗ ,
∗ Atomic and Molecular Physics Lab, Department of Applied Physics Indian Institute of Technology (ISM), Dhanbad, Jharkhand 826004, India
Topic: A
Positrons are not easily obtainable as com- tical potential (SCOP) formalism [4,5] is used pared to their electronic counterpart. However, in this work to calculate positron scattering to- in recent times the progress in trapping methods tal cross sections over a wide energy range from and their storage has now permitted the accumu- positronium formation threshold to 5000 eV for lation of a adequate number of low-temperature small hydrocarbons. To estimate direct ioniza- positrons to form plasma. Positrons annihilate tion cross section the modified form of CSP-ic electrons and because of having opposite charge [6] method is used. Total ionization and positro- and same mass number they can combine with nium formation cross section by positron impact electrons to form neutral plasmas having dynam- are also evaluated. ical symmetry between the charged species. Re- Figure 1 shows the total cross section for cent years have seen a huge interest in laboratory positron scattering from methane. There is an experiments on electron-positron plasmas such as excellent agreement of the present and previous PAX/APEX experiment[1]. experimental data. The present work is devoted to study var- ious cross sections for C2-C3 hydrocarbons via positron scattering. The present work is under- taken because the present set of targets has nu- merous applications in various fields. Hydrocar- bons are one of the abundant sources in plasma materials which are formed by chemical erosion of the surface occurring due to plasma-wall in- teractions, hence they become one of the major contamination sources in the hydrogenic plasma. The composition of the hydrocarbon fluxes flow- ing inside the plasma covers a wide spectrum of molecules from methane to propane [2]. The discharge of more complex C2-C3 hydrocarbons Figure 1. Positron scattering from ethene becomes increasingly vital as the impact energy of plasma ions striking the surface decreases [2]. These hydrocarbons play a very significant role in plasma diagnostics in the Tokamak fusion References divertor, in edge plasmas of magnetically con- [1] T. S. Pedersen et al. 2012 New J. Phys. 14 035010 fined high temperature hydrogen plasma and also in low temperature plasma processing. Apart [2] H. Deutsch et al. 2000 J. Phys. B: At. Mol Opt. from their application in plasma science they are Phys. 33 L865 widely studied in the field of astrophysics where [3] H. Nishimura and H. Tawara 1994 J. Phys. B: At. they are observed as an important constituent in Mol Opt. Phys. 27 2063 the planetary and cometary atmosphere [3]. To [4] S. Singh et al. 2016 J. Chem Phys. A 120 5685 understand the behaviour of these molecules in plasma and space physics, reliable cross sections [5] S. Singh et al. 2017 J. Phys. B: At. Mol Opt. Phys. are needed. Cross sections form an integral part 50 135202 in studying collision dynamics of any target. [6] S. Singh and B. Antony 2017 J. Appl. Phys. 121 The modified form of spherical complex op- 244903 1E-mail: [email protected] 2E-mail: [email protected]
82 ISAMP TC-7, 6 8 January, 2018, Tirupati CA027 Vinodkumar − Dissociative electron attachment study of di & tri atomic molecule 1 2 3 Minaxi Vinodkumar ∗ , Hitesh Yadav† , P. C. Vinodkumar †
∗ Electronics Department, V. P. & R. P. T. P. Science College, Vallabh Vidyanagar - 388120, Gujarat, India † Department of Physics, Sardar Patel University, Vallabh Vidyanagar - 388120, Gujarat, India
Topic: A
Low energy collision study below 10 eV is sig- the conference. nificant due to the formation of short-lived ani-
ons (resonances) which are responsible for dis- sociative electron attachment (DEA) that leads
Srivastava )
0.01
Present to fragmentation of target to produce neutral 2 Å and anionic fragments through vibronic excita- ( tions. Such processes are very important in
under-standing the local chemistry induced by 1E-3 electron target interaction. This phenomenon is simply represented as
1E-4 DEA Cross section
0 2 4 6 8 10 12 14 16 18 20
AB + e− A + B− or A− + B (1) E eV → i
Figure 1. H− anion from HCl, where the solid line represents the present result and solid sphere repre- Dissociative electron attachment (DEA) pro- sents the measured results of Orient and Srivastava cess, despite being an important phenomenon [7] in the field of plasma physics [1], environmen- tal science [2] and radiation damage [3], finds sparse attention by theoretical groups. On the contrary, substantial progress has been made in Acknowledgment experimental studies of this process, largely be- cause of new experimental techniques involving Dr. Minaxi Vinodkumar acknowledges DST- electron beams with high energy resolution. SERB, New Delhi for Major research project [EMR/2016/000470] for financial support under which part of this work is carried out. We have used R-matrix [4] method for low en- References ergy computation of eigenphases through which resonance width and resonant energy are com- [1] Chutjian et al., 1996 Phys. Rep. 264, 393. puted which are important inputs for com-puting [2] Q-B. Lu and L. Sanche, 2001 Phys. Rev. Lett. 87, the DEA cross sections via. Quantemol-N soft- 078501 ware [5, 6]. [3] L. Sanche, 2005 Eur. Phys. J. D. 35, 367. [4] M. Vinodkumar et al. 2016 Phys. Rev. A 93, 012702. Fig. 1 shows the result of DEA process of H- anion formation from HCl. The present theoreti- [5] J. J. Munro et al. 2012 J. Phys. Conf. Ser. 388, cal data is in good agreement with the experi- 012013. mental data of Orient and Srivastava [7] above [6] H. Yadav et. al, 2017 Molecular Physics, 115, 10 eV. Below 10 eV present result are lower com- 952.. pare to experimental data of Orient and Srivas- [7] O. J. Orient and S K Srivastava, 1985 Phys. Rev. tava [7]. The detailed results will be presented in A 32, 2678. 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected]
83 ISAMP TC-7, 6 8 January, 2018, Tirupati CA028 Yadav − Electron impact scattering studies of Halomethane (CH3X, X = F, Cl, Br, I)
1 2 3 4 Hitesh Yadav ∗ , Minaxi Vinodkumar † , Chetan Limbachiya ‡ , P. C. Vinodkumar ∗
∗ Department of Physics, Sardar Patel University, Vallabh Vidyanagar - 388120, Gujarat, India † Electronics Department, V. P. & R. P. T. P. Science College, Vallabh Vidyanagar - 388120, Gujarat, India ‡ Department of Applied Physics, The M. S. University of Baroda, Vadodara - 390001, Gujarat, India
Topic: A
Electron molecule scattering phenomenon are and Krzysztofowicz & Szmytkowski [4]. of great importance and have various applica- tions in the allied fields. Scattering cross sections
helps in determining the rates at which gas phase 60
Present TCS
processes and chemical reactions happen whether Benitez et. al.
50 in industrial sector or in planetary atmospheres Krzysztofow icz
[1] 40 e-CH Br )
3 2 Å
30 In this paper, we mainly discuss about the
20
electron impact molecular scattering cross sec- TCS ( tions of Halomethane molecules (CH X,X = 3 10 F, Cl, Br, I). Halomethanes are tetrahedral
0
molecules and are derivatives of methane (CH4) 10 100 1000 with one of the hydrogen atom being replaced by E (eV) one of the halogen atoms i.e. F, Cl, Br, or I. This i
Halomethane are available naturally as well as Figure 1. Total Cross section of CH3Br molecule, human made compounds as they attracted wide where the solid line represents the present com- attention due to their chemical activities. They puted result, while the solid sphere represents the become active when exposed to ultraviolet light Benitez et. al [3] and dot star represents the at high altitudes and destroy the earth’s protec- Krzysztofowicz & Szmytkowski [4] measured re- tive ozone layer. sults.
The physical properties of Halomethanes de- pends on the number and identity of the halogen atoms in the molecule. In general halomethanes Acknowledgment are volatile but less so than of methane because of Dr. Minaxi Vinodkumar acknowledges DST- the polarizability of the halides and the polarity SERB, New Delhi for Major research project of the molecules makes them useful as solvents. [EMR/2016/000470] for financial support under which part of this work is carried out. We have used the well established theoreti- cal method Spherical Complex Optical Poten- References tial (SCOP) [2] for the computation of Elastic, Inelastic and total cross sections. And Com- [1] G. W. F. Drake, 2006 Handbook of Atomic, Molec- plex Spherical Potential - ionization contribution ular and Optical Physics, Springer, pp-890. (CSP-ic) [2] for the computation of ionization [2] H. Yadav et. al, 2017 Molecular Physics, 115, 952. and electronic excitation cross sections. In fig- ure 1, we present the total cross section of the [3] A. Benitez et. al, 1988 J. Chem. Phys. 88, 6691. CH3Br molecule, which is in very good agree- [4] A. M. Krzysztofowicz & C. Szmytkowski, 1994 ment with measured data of Benitez et. al [3] Chem. Phys. Lett. 219, 86. 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 4E-mail: [email protected]
84 ISAMP TC-7, 6 8 January, 2018, Tirupati CA029D Sharma − Electron scattering from endohedrally confined Ca atoms
S. Bharti1, P. Malkar1, L. Sharma* 1, B. K. Sahoo2,3 and R. Srivastava1
1Department of Physics, IIT Roorkee, Roorkee – 247667, Uttarakhand, India 2Atomic and Molecular Physics Division, Physical Research Laboratory, Navrangpura, Ahmedabad 380009, India 3State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
Topic: A, D
The spatial entrapment of atoms or molecules is of the potential well. Effect of correlations as well possible in nature as well as artificially e.g., as encapsulation on the first excitation energy, impurity atoms in mesoscopic scale semiconductor ionization potential and dipole polarizability are artificial structures, molecular zeolite sieves, studied in detail. Results are obtained for fullerenes and quantum devices [1]. The differential and integrated cross sections for free as confinement of atoms leads to distinct and well as confined Ca. We compare our results for interesting changes in their physical and chemical free Ca with the experimental data [4] and other properties. theoretical calculations using DF method [5]. An In the present work we focus on endohedral example of such comparison is shown in figure 1 entrapment of atom inside fullerene cage which can for differential cross section (DCS) at 20 eV. The be synthesized in laboratory owing to rapid behaviour of the cross sections with increasing well development in experimental technology. Although depth and with the importance of correlation effects all fullerenes can confine endoheral atoms, C60, in will be discussed in detail at the conference. particular, is more interesting among all the fullerenes as it can be approximated by a spherical ball with a single endohedral atom kept at the center of this approximate ball. Thus the altered energy levels of the encapsulated atom can be considered as the result of a potential that is slightly perturbed from having spherical symmetry. Recently, Hasoğlu et al have investigated correlation effects of endohedral confinement on the energy of Be, Mg, and Ca atoms using non- relativistic Hartree-Fock method [2]. They mentioned the possibility of confinement of Ca atom at the center of the C60 shell, giving rise to a stable equilibrium. Kumar et al investigated non dipole effects in photoionization of outer 4s shell of Ca entrapped in a spherical attractive well potential Figure 1. DCS for e-Ca elastic scattering at 20 eV. [3]. It is therefore interesting to understand the effect of such an environment on the structure of a References captured Ca atom. We have investigated elastic electron scattering [1] W. Jaskólski, 1996, Phys. Rep. 27 1. from Ca atom trapped inside the endohedral [2] Hasoğlu et al. 2016, Phys. Rev. A 93 022512. fullerene C60 molecule using optical model [3] Kumar et al. 2014 J. Phys. B 47 185003. potential. The confining potential is taken as an [4] S. Milisavljevic et. al. 2005 J. Phys. B: At. Mol. attractive spherically symmetric potential well. Opt. Phys. 38 2371 Relativistic coupled cluster (RCC) and Dirac-Fock [5] M. Hasan et. Al. 2014 Can. J. Phys. 92 206-215 methods (DF) are employed to obtain the wave functions of the confined Ca atom at various depths
* E-mail: [email protected] [email protected]/in [email protected]
85 ISAMP TC-7, 6 8 January, 2018, Tirupati CA030 Chakraborty − Molecular effects in L shell ionization of Au and Bi by slow Ag ions
Kajol Chakraborty†* 1, Ruchika Gupta†*, Ch. Vikar Ahmad†*, Tulika Sharma#, Anjali Rani*, Akhil Jhingan+ , Deepak Swami+ , Samit K. Mandal* and Punita Verma† 2
† Department of Physics, Kalindi College, University of Delhi, East Patel Nagar, Delhi – 110008, India * Department of Physics and Astrophysics, University of Delhi, Delhi – 110007, India # Amity Institute of Applied Sciences, Amity University, Noida – 201313, India + Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi – 110067, India Topic: A
Heavy ion induced inner shell ionization produces multiple vacancies in the outer shell simultaneous to the vacancies in the inner shell thus creating a complicated electronic configu- ration [1,2]. Relatively slow, heavy ion atom collisions which are slow compared to the orbital velocity of the innermost electrons K or L (vion
1 E-mail: [email protected] 2 E-mail: [email protected]
86 ISAMP TC-7, 6 8 January, 2018, Tirupati CA031 Gorai − VUV Spectroscopy of Dodecane Molecule using synchrotron radiation
Kiran Kumar Gorai*1, Param Jeet Singh, Aparna Shastri, S. N. Jha
*Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai - 400085.
Topic: A. Quantum collisions and Spectroscopy of atoms, molecules, clusters, and ions
Dodecane (C12H26), an acyclic alkane is a calculations have been performed for the colorless liquid of the paraffin family and is analysis of electronic excited states. The widely used as a diluent for tributyl phosphate simulated stick spectrum agrees fairly well with in nuclear waste reprocessing [1]. In recent the experimental spectrum. Details of the years dodecane has gathered considerable experiment, theoretical calculations and spectral attention as a possible surrogate for kerosene- analysis will be discussed. based fuels such as Jet-A, S-8 etc. [2]. Liquid alkanes are also ideal candidates for immersion lithography due to their high refractive index and near transparency in the 193 nm region [3]. Combustion and pyrolysis processes of alkanes, relevant to their use as fuels, typically involve dissociation through excited vibrational or elec- tronic states [4]. In order to understand the chemical reactions involved in all these processes at a microscopic level, it is essential to have detailed information about the ground and excited state structure of the molecule. So far there have been very few reports in literature regarding the spectroscopy of the dodecane molecule [3, 5], and no reports on its electronically excited states. With this motiva- Figure 1 VUV absorption spectra of dodecane record- tion to obtain excited state information on ed at various pressures using the HRVUV beamline at dodecane, photoabsorption experiments in the the Indus-1 synchrotron radiation source. wavelength region 1200–2000 Å have been carried out using High Resolution Ultra Violet References (HRVUV) beamline [6] at the Indus-1 [1] Sung Ho Ha et al. 2010, Korean J. Chem. En synchrotron radiation source, RRCAT, Indore 27(5), 1360 (cf. Figure 1). Samples with stated purity of > [2] Tim Edwards et al. 2001, Journal of Propulsion 99% are further purified with several freeze- and Power 17, 2 pump-thaw cycle in order to remove volatile [3] J Sebek et al. 2011 Phys. Chem. Chem. Phys. 13, impurities. Absorption spectra of dodecane, 12724 recorded at several pressures, are shown in [4] S.M. Wu et al. 2000, J. Phys. Chem A 104, 7189 Figure-1. The observed spectra consist of a very [5] D.R. Worton et al. 2015, Environ. Sci. Technol intense broad band at ~1200-1700 Å and a weak 49, 131130 band at ~1900 Å. An overall red shift for the [6] P.J. Singh et al. 2011, Nucl. Intrum. Meth A, 634, 113 broad transition ~1200-1700 Å with increasing pressure is seen in the observed spectrum. To aid the analysis, geometry optimization and vibrational frequency calculations of neutral and ionized dodecane have been carried out using density functional theory (DFT) for a variety of basis sets and correlation functionals. The optimized geometry and calculated vibrational frequencies for the lowest energy conformer, which is predicted to be of Cs sym- metry, are in good agreement with earlier literature [3]. Time dependent DFT (TDDFT)
1E-mail: [email protected] 87 ISAMP TC-7, 6 8 January, 2018, Tirupati CA032 Gupta − Detecting the elemental constitution of environmental samples of Delhi and sur- rounding regions using XRF spectroscopy
Ruchika Gupta*† 1, Ch. Vikar Ahmad*†, Kajol Chakraborty*†, Preeti Rao#, Raj Mittal#, Chirashree Ghosh$ and Punita Verma* 2
* Department of Physics, Kalindi College, University of Delhi, East Patel Nagar, Delhi – 110008, India
† Department of Physics and Astrophysics, University of Delhi, Delhi – 110007, India # Department of Physics, Punjabi University, Patiala – 147002, India
$Department of Environmental Studies, University of Delhi, Delhi – 110007
Topic: A.
Metal toxicity has proven to be a major threat ing a resolution of 145 eV at 5.9 keV [3]. Each for human life as there are several health risks asso- pellet was irradiated for 1000 seconds for statis- ciated with it. Metal bio-magnification within living tical precision. Figure 1 shows the recorded systems is a persisting problem. Investigations on XRF spectrum of a soil sample. determining the contamination level of environmen- tal samples has been going on for a substantial amount of time in India as well as all over the world. Electro-chemical, chemical or spectroscopic techniques have been popular for the above- men- tioned detection purpose. These methods although being easier and compatible, lack sensitivity for multi element detection and accuracy. Thus there is a need for a better technique which can detect con- taminants in trace and ultra-trace amounts and also has multi element detection capacity apart from ad- justing negligible to nil interference problems. Pre- sent work is an effort to identify contamination in differentl soil and plant samples of diverse land use sites in Delhi using XRF spectroscopy. X-ray Fluorescence (XRF) spectroscopy specifi- Figure 1. XRF spectrum of soil sample. cally a versatile method for composition analysis, is non-destructive, has high sensitivity with multi- Details of these preliminary measurements element detection capability. This method has high performed to quantify the efficiency of the set- sensitivity in detecting elements with atomic num- up will be presented. Investigation will be con- ber in the range of 18 1 E-mail: [email protected] 2 E-mail: [email protected] 88 ISAMP TC-7, 6 8 January, 2018, Tirupati CA033 KumarSarvesh − Characterization of thin aluminized polypropylene backed atomic targets using 2 MeV He+ Ions. Sarvesh Kumar1,2, Sunil Kumar2, Deepak Kumar Swami3, D.P. Goyal1, and T. Nandi3§ * 1Indira Gandhi University Meerpur, Rewari (Haryana) India. 2Department of Applied Sciences, Chitkara University, Himachal Pradesh 174103, India. 3Inter-University Accelerator Centre, New Delhi 110067, India. Topic: A: Quantum Collisions and Spectroscopy of atoms, molecules, clusters and ions. Thin atomic targets have been the key re- 5 µg/cm2) elements deposited on 3µm alumi- quirement in ion-atom collisions since decades. nized Mylar. To meet the single collision conditions in inner The above described targets were used for L shell ionization studies such targets have their x ray measurements some part of which is al- own importance. ready published [3]. Bi thickness was found RBS (Rutherford backscattering Spec- 28.9 angstroms with micro-density of 9.81 g/cc trometry) has been a proven tool for elemental yields. While the Aluminized Polypropylene analysis, chemical composition, depth profiling thickness was found to be Al surface with mi- and uniformity of thin targets. In this article, we cro-density of 2.70 g/cc yields 2.2318e+017 At- report characterization of ultra-thin (3-5μg/cm2) oms/cm2 (370.5 angstroms). targets of high Z, (Z=64-83) deposited on thin aluminized polypropylene. The target thickness was kept thin to meet single collision condition in ion atom col- lisions and for inner-shell ionization studies. Cross examination of thickness was done using alpha particle energy loss measurement. And a reasonable agreement was found between the two different types of measurements. RBS measurements were performed us- ing NEC’s 5SDH-2 Tandem Pelletron Accelera- tor at IUAC, New Delhi using 2 MeV He+ Beam. The backscattered He were detected us- ing SSB Detector at 1660. [1] In this characterization thin atomic tar- Figure 1. RBS spectra of Bi and Pt bombarded by 2 gets (Bi and Pt) were bombarded by 2.000 MeV MeV He+ ions 4He+ and charge of 4.00 uCoul @ 2.44 nA. En- ergy of backscattered particles was collected at References 1660 using SSBD (Silicon Surface Barrier De- [1] http://www.ijsrd.com/articles/NCILP018.pdf tector with FWHM of 25 KeV). [2] S. Kalkal et.al., “Fabrication of 90,94Zr targets These targets were made using the vac- on carbon backing,” Nucl. Instr. Meth. A, vol. 613, uum deposition technique [2]. The target uni- no. 2, pp. 190–194, 2010. formity was verified to be reasonable. [3] S. Kumar et al., “L shell x-ray production in The thickness and the uniformity of high-Z elements using 4-6 MeV/u fluorine ions,” these targets were measured by the energy loss Nucl. Instruments Methods Phys. Res. Sect. B Beam method using alpha particles from a radioactive Interact. with Mater. Atoms, vol. 395, pp. 39–51, 2017. decay of 241Am and compared by RBS meas- urement. Targets of 78Pt and 83Bi (thickness ~ E-mail: [email protected] E-mail: [email protected] 89 ISAMP TC-7, 6 8 January, 2018, Tirupati CA034 KumarSunil − L shell x-ray production in ultra-thin 76Os using 4-6 MeV/u fluorine ions. Sunil Kumar1*, Sarvesh Kumar1,2, Deepak Kr Swami3 M. Oswal4, N. Singh4, D. Mehta4 D.P. Goyal2 and T. Nandi3§ 1Department of Applied Sciences, Chitkara University, Himachal Pradesh 174103, India. 2Indira Gandhi University Meerpur, Rewari (Haryana) India 3Inter-University Accelerator Centre, New Delhi110067, India. 4Department of Physics, Panjab University, Chandigarh160014, India. Topic: A: Quantum Collisions and Spectroscopy of atoms, molecules, clusters and ions. The measurement of emitted x-rays from 0.35357≤ vP/vT ≤ 0.433033 indicates that the targets has resulted in major advances in radia- present data are in the asymmetric and slow col- tion [1], plasma [2], atomic and nuclear physics lision regime. Experimental details are pub- [3], and in particle induced x-ray emission lished in [5]. (PIXE) technique [4]. Since the beginning of PIXE, light ions such as protons or alphas are normally used, nevertheless there is an increas- ing interest towards heavy ions due to higher cross sections and thereby better sensitivity. However, multiple ionization effect is more se- vere in heavy ion induced data and the effect is rarely addressed for the x-ray emission ele- mental analysis even though heavy ions is used. The L x-ray production cross-sections have been measured in ultra-thin targets ionized by the 76–114 MeV 19F ions. Figure 2. Osmium L X-ray intensity ratios with re- spect to Lα transition. Figure 2 shows the L x-ray intensity ratios of Osmium with respect to Lα transition. References [1] Satoh T et.al. 2015 Int. J. PIXE 25 147–52. [2] Sharma P et.al. 2016 Phys. Plasmas 23 83102. [3] Dyson N A et.al. 1990 (Cambridge University Press). [4] Antoszewska-Moneta M et.al. 2015 Eur. Phys. Figure 1 L X-rays of Osmium ionized by 4 MeV/u F19. 9 J. D 69 77. [5] Kumar S et.al. 2017 Nuclear Instr.& Methods B A typical spectrum is shown in Fig.1. Here, 395,39-51. ZP/ZT = 0.11842105 and the projectile velocity to the orbital velocity ratio in the range of 1E-mail: [email protected] 3 E-mail: [email protected] 90 ISAMP TC-7, 6 8 January, 2018, Tirupati CA036 Modak − Ionization cross section of water clusters ((H2O)n,n=1-4) by electron impact Paresh Modak 1, Vraj Patel 2, Himani Tomer 3, Bobby Antony 4 Department of Applied Physics, Indian Institute of Technology (Indian School of Mines) Dhanbad Topic: A Electron impact processes in aqueous envi- single monomer and a correspond to hard sphere ronment have great importance in physiochem- packing fraction. ical study of a system. Radicals and ions pro- The ionization cross section for water dimer duced during these processes interact with the is reported in Fig.1. Present calculation shows surroundings and give crucial information of the good agreement in cross section throughout the interaction dynamics. Water clusters play sig- energy range of present interest. The difference nificant role in such environment and help to in cross section value is almost 2% throughout understand the quantum chemical processes of the present energy range. This is due to differ- various applied fields of science such as waste ent method used to consider the ionization con- remediation, environmental cleanup, chemistry tribution form a single monomer. Joshipura et of ionosphere, radiation processing, nuclear re- al. used an geometric approach to include the action, medical diagnosis etc. [1]. Also water screening effect where as we have used an empir- clusters have crucial role in a atomic plant for ically determined value of a=0.84 in Eq.1. cooling [2]. Hence, precise knowledge of electron- water cluster interaction is necessary for the un- derstanding of physiochemical processes occur- ring in these environments. The ionization cross section is used as input parameter for modeling it along with its reaction rates. The present study reports the results of the- oretical investigation of ionization cross section for (H2O)n (n=1-4) by electron impact from ion- ization threshold to 5 keV. For this we employed CSP-ic [3] formalism for each monomer. Then the distance of monomers from its nearest neigh- bor is used for further calculations. This method is well established for the computation of ioniza- Figure 1. Ionization cross section of water dimer tion cross section from the inelastic channels for with reported data targets in its gaseous ground state. The vibra- tional and rotational contributions are neglected in the present energy range. Then ionization cross section for the cluster is calculated using References the following modified additive rule for cluster [1] Garrett Bruce C.et al. Chem Rev 2005 355 a σion(Xn)=n σion(X) where n is number of monomer present in the [2] Tachikawa et al. J Phy Chem A 2004 7853 cluster and σion(X) is ionization cross section of a [3] Joshipuraet al. Phys Rev A 2004 022705-2 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 4E-mail: [email protected] 91 ISAMP TC-7, 6 8 January, 2018, Tirupati CA037 Sharma − Disentangling charge exchange processes in bulk from surface Prashant Sharma*1 and T. Nandi*2 *Inter-University Accelerator Centre, JNU Campus, New Delhi110067, India. Topic: A Charge exchange processes of projectile netic measurements or a suitable semi empirical ions traversing a solid is highly intricate because of formula. In the present case, we have used Sciwietz coexistence of many physical phenomena including formalism [6]. Fig.1 demonstrates an example of ionization, excitation, radiative decay, Auger decay, disentanglement of charge exchange processes in electron decay, non-radiative and radiative electron different regimes viz. bulk, bulk plus REC process, capture, multiple vacancy creations, electron loss to and integral effect of the foil. continuum, electron capture to continuum multiple electron capture, radiative electron capture in the continuum, three-electron-Auger process, radiative double electron capture, etc. These charge chang- ing and charge exchange processes originate from either bulk or exit surface of the foil for the fast ion- atom collisions. REC process can come from both the bulk as well as surface and have no lifetime structure. Whereas the wake riding electron [1] driven processes at the exit surface gives rise to ex- cited states including the circular Rydberg states [2]. Further, influence of wake and dynamic screen- ing effect [1] can also not be ignored. Hence, disen- Fig.1. Disentanglement of charge exchange pro- tangling the processes cropping up at the bulk and cesses occurring in the bulk, the bulk as well as surface in extremely difficult. On the other hand, x- REC process, and the total foil (bulk and exit sur- ray spectroscopy technique [3] can measure the face). charge state distributions (CSD) through the charac- References teristic Kα X-ray line that occurs due to the atomic [1] J. Burgdörfer 1992 Nucl. Instru. Meth. B67 1 processes responsible in the bulk only [4], whereas [2] T. Nandi 2008 The Astrophys. J. 673 L103 [3] J. P. Santos et al. 2010 Phys. Rev. A 82 062516 REC photo peak is used to obtain the CSDs for an [4] P. Sharma et al. 2016 Phys. Lett. A 380 182 intermediate stage responsible for the processes [5] P. Sharma 2017 et al. submitted to Euro. Phys. Lett. [6] G. Schiwietz et al. 2004 Nucl. Instru. Meth. B 226 occurring in the bulk and REC [5] itself. The inte- 683. gral picture is of course obtained from electromag- 1E-mail: [email protected] 2E-mail: [email protected] 92 ISAMP TC-7, 6 8 January, 2018, Tirupati CA038 Pal − Determination of energy and angle dependent electron ionization cross sections for methylamines R. Singh, Manoj Kumar, N. Kumar and S. Pal* Department of Physics, M.M.H. College, Ghaziabad-201001 (UP) Topic: (A) Quantum collision and Spectroscopy of atoms, molecules, clusters, and ions. The absolute photon and electron spectra of integral total ionization cross sections in the im- methylamines are of interest and importance in pinging electron energy range varying from ioniza- many areas of science and technology including tion threshold to 1000 eV and compared those with those of astrophysics, laser physics, photochemi- the available experimental and theoretical data for stry, or in other applications where the interaction mono-methylamine [4-5]. The present results reveal of high energy radiation or particles with these mo- god agreement with the available results. lecules is to be understood [1]. In the present work, differential cross sections References as a function of energy of the secondary/ ejected [1] G.R.Burton et al. 1994,. Can. J. Chem. 72 electron in ionization of mono-methylamine 529. (CH3)NH2, di-methylamine (CH3)2NH and tri- [2] R.Singh et al. 2013, J. Elect. Spectr. Relt. methylamine (CH3)3N by electron impact are calcu- Phen. 185 635. lated at the fixed incident electron energies viz. 100 [3] R.Kumar, 2013 Rapid Commun. Mass Spec- and 200 eV. The isotropic angular behaviours of trom. 27 223. cross sections at the same energies are also eva- [4] M.Vinodkumar et al. (2008) J. Phys. (Conf. luated. The modified JK semi empirical formulation Ser.) 115 012013. [2-3], which requires the oscillator strength data as [5] F.M. Silva et al. (2014) Eur. Phys. D 68:12. input has been employed. In absence of any theoret- ical and or experimental data, we have derived * E-mail: [email protected] 93 ISAMP TC-7, 6 8 January, 2018, Tirupati CA039 Natarajan − Kα X-RAYS FROM VARIUOSLY IONIZED IODINE Anuradha Naratajan * 1 and L.Natarajan + 2 *Department of Physics, SIWS College, Wadala, Mumbai-400031 +Department of Physics, University of Mumbai, Mumbai-400098 Topic: A A study on the X-ray satellites resulting from the iodine from 1s-2p transitions with various L rearrangement of initial vacancies is essential in shell ionic states in an otherwise closed shell understanding the ultrafast dynamics of the configuration. The calculations have been ionization process. In addition, in recent years, carried out using multi-configuration Dirac-Fock the advantage of tunable monochromatic X-ray wavefunctions with the inclusion of magnetic sources over broad band radiation sources in interaction, retardation and quantum practical applications and high intensity X-ray electrodynamics effects [3]. The intrinsic Free Electron laser needed to produce a high variations in the transition parameters with energy density plasmas have been explored [1,2] degree of ionization have been analyzed. To the . As K X-ray data on multiply ionized high Z best of our knowledge, no theoretical or atoms are largely unknown, in this work, we experimental data exist except for the Kα fine investigate the structure of K shell resonances of structure lines. References [1] M. Montenegro et al. 2009 J. Phys. Chem. A 113, 12364 [2] L. Young et al.2010 Nature 466, 56 [3] P. Jonsson et al. 2013 Comput. Phys. Commun.184, 2197 ______ [email protected] Email:2 [email protected] 94 ISAMP TC-7, 6 8 January, 2018, Tirupati CA040 Ankita − The Spectrum of Doubly Ionized Silver: Ag III S. Ankita*1 and A. Tauheed2 Department of Physics, Aligarh Muslim University, Aligarh-202002, India Topic:A Ag III, a member of Rh I isoelectronic series, The silver spectra were recorded on a 3-m has 4p64d9 as its ground configuration. The normal incidence vacuum spectrograph at St. F. regular outer electronic excitation leads to the X. University, Canada using a triggered spark configurations of the type 4d8np (n≥5), 4d8nf source in the wavelength region 345-2071 Å. (n≥4) and 4d8nd (n≥5), 4d8ns (n≥5) in the odd We re-investigated the earlier results pub- and even parity system respectively. The core lished by Gilbert [2] and Benschop et al [3] and excitation of the above said configurations also found a number of ambiguities in ref [3]. There- leads to the 4p54d10, 4d75p2, 4d75s2 and 4d75s5p fore, a few level values of the configuration configurations. 4d85p have been revised. The work is in the The analysis of this spectrum was reported progress and the latest findings on 4d8(4f+6p) by Gibbs and White [1], Gilbert [2] and configurations will be presented at the confer- Benschop et al [3]. At present, only two excited ence. configurations namely 4d85p and 4d85s have been studied along with the ground doublet. The References two major configurations arising out of the 8 8 [1] Gibbs et al 1928, Proc. Natl. Acad. Sci. Amer. ground state excitation namely 4d 4f and 4d 6p 14, 559-564. remain untouched. In the present work we have [2] W. P. Gilbert, 1935, Phys. Rev. 48, 338-342. undertaken the study of these configurations [3] Benschop et al, 1975, Can. J. Phys. 53, 498-503. through the transition array 4d9- 4d8(4f+6p) and [4] R. D. Cowan, 1981, The Theory of Atomic Structure with the aid of Relativistic Hartree-Fock and and Spectra, (Berkeley, CA: University of California least squares fitted parametric calculations Press) and Cowan code package for Windows by A K using Cowan’s code [4]. Kramida E-mail: [email protected] E-mail: [email protected] 95 ISAMP TC-7, 6 8 January, 2018, Tirupati CA041 Sen − Study Molecular Dissociation Dynamics using Velocity Map Imaging Arnab Sen, Anbu Selvem Venkatachalam, Shilpa Rani Sahu, Ram Gopal, Vandana Sharma Department of Physics, IISER Pune, Pune -411008, Maharashtra, India Topic: A. Quantum collisions and Spectroscopy of atoms, molecules, clusters, and ions + + We indigenously designed and fabricated a electron molecules, O 2 and CH3I following its simple ion imaging spectrometer based on a ionization in a strong laser field (3x1013 W/cm2, 800 single ion extraction field, lensing field and a nm, 30 fs) during the conference. field-free drift region [1] coupled with a posi- tion sensitive delay line anode detector which offers 3D ion momentum imaging capabilities. The ion imaging spectrometer also known as Ve- locity Map Imaging (VMI) spectrometer (Fig. 1) employs a field configuration to collect ions from the reaction volume and focusses ions with the same initial velocities them onto the same radial coordinate on the detector. When the detector records the triplet (xion, yion and, Figure 1. Schematic diagram of electrostatic lens tion) of each ion hit, where (xion, yion) are the position used for velocity map imaging of photodissociation. coordinates of the ion splat and tion the flight time of the ion relative to its generation. Depending on the References geometry of the spectrometer and the applied poten- tials, the initial 3D momentum (px, py and pz) can be [1] André T. J. B. Eppink and David H. Parker, Rev. reconstructed. Sci. Inst, 68, 3477 (1997) I will report the performance of this spectrometer using the example of a dissociation of multi- E-mail: [email protected] 96 ISAMP TC-7, 6 8 January, 2018, Tirupati CA042 Singh − Synchrotron based VUV spectroscopy of dimethylacetamide Param Jeet Singh1, Asim Kumar Das, Kiran Kumar Gorai, Aparna Shastri, B N Raja Sekhar, Sunan- da K, S N Jha, N K Sahoo. Atomic & Molecular Physics Division, BARC, Mumbai – 400085, India. Topic: A. Quantum collisions and Spectroscopy of atoms, molecules, clusters, and ions Abstract Vacuum ultraviolet (VUV) photoabsorption spectroscopic study of dimethyl acetamide (DMAc) has been performed using synchrotron radiation. Band system appearing ~1700Å has been resolved into three components. Analysis of the observed spectrum is supported with DFT and TDDFT based quantum chemical calculations. In recent years, diamide-based extractants tions will be presented and discussed in this pa- have attracted attention of nuclear industry as per. alternate solvents for nuclear fuel reprocessing [1]. Several investigations have been reported to optimize the amide structure for their best ex- tracting properties [1-4]. Dimethylacetamide (DMAc) is also commonly used as an reaction intermediate in adhesive industry, pharmaceuti- cals, synthesis of pesticides and plasticizers [5] and is a potency reproductive toxicant [6]. In the atmosphere, DMAc undergoes photolysis and reacts with OH, Cl, O3 and NO3 radicals [7]. A few photochemical reaction dynamics take place through excited electronic states. There is very little literature[8] on the interac- tion of UV and VUV radiation with this mole- cule and the gas-phase photochemistry of DMAc is not well understood. Figure 1 VUV photoabsorption spectrum of dimethyla- cetamide at 0.02 mbar recorded using synchrotron radia- VUV spectroscopic study of DMAc has tion been performed using synchrotron radiation from Indus-1 source, RRCAT, Indore. Photoab- References sorption experiments in the wavelength range of 1050–2300Å are carried out using a 0.5m stain- [1] A. Rao, B.S. Tomar, 2016, Separation and less steel gas cell coupled to photophysics Purification Technology 161, 159 beamline [9]. Samples of DMAc with stated [2] P.K.M. S.A. Ansari, D.R. Raut, V.C. Adya, S.K. Thulasidas, V.K. Manchanda, 2008, Separation and purity of >99% were further purified using Purification Technology 63, 4. freeze-pump-thaw method to remove the vola- [3] S.A. Ansari, N. Kumari, D.R. Raut, P. Kandwal, tile impurities. Xenon atomic lines are used for P.K. Mohapatra, 2016, Separation and Purification wavelength calibration. Spectra are recorded at Technology 159, 161 several pressures for resolving weak features; [4] V.K. Manchanda, P.N. Pathak, 2004, Separation and Figure 1 shows representative spectra at 0.02 Purification Technology 35, 85. mbar. Analysis of the experimental spectrum is [5] H. Cheung, R.S. Tanke, G.P. Torrence, 2000, aided by density functional theory (DFT) and Ullmann's Encyclopedia of Industrial Chemistry, time dependent DFT (TDDFT) based quantum Wiley-VCH Verlag GmbH & Co. KGaA. chemical calculations. In the present study, [6] European Chemicals Agency, 2014, Opinion on N,N-Dimethylacetamide (DMAC). mainly four broad absorption bands are ob- [7] G. Solignac, A. Mellouki, G. Le Bras, I. Barnes, T. served peaking at 1095Å, ~1700Å, 1915 Å and Benter, 2005, Journal of Photochemistry and 2150 Å. A band reported ~1700Å by Kaya et. al Photobiology A: Chemistry 176, 136. [8] has been resolved into three features in the [8] K. Kaya, S. Nagakura, 1967, Theoret. Chim. Acta 7, present study. All the observed bands are due to 7. electronic excitations. The observed bands have [9] N.C. Das, B.N. Raja Sekhar, S. Padmanabhan, A. been assigned based on the calculations. Elec- Shastri, S.N. Jha, S.S. Bhattacharya, S. Bhat, A.K. tronic states and corresponding vibrational en- Sinha, V.C. Sahani, 2003, Journal of Optics 32, 169. ergy levels involved in these observed transi- 1E-mail: [email protected] 97 ISAMP TC-7, 6 8 January, 2018, Tirupati CA043 Sinha − Positron Scattering Cross Sections for Methyl Halides 1 2 3 Nidhi Sinha∗ , Durgesini Patel∗ and Bobby Antony∗ ∗Department of Applied Physics, IIT (Indian School of Mines) Dhanbad, Jharkhand-826004, India Topic: A Positron scattering from various atomic and plot to get an idea of the contribution from the molecular targets have driven significant atten- inelastic channel in the scattering process at dif- tion from the scientific community in the re- ferent energies. There is significant disagreement cent decades. This rests on the vast range of between the present results and that of Kimura applications of such interaction, viz. plasma, et al.[4] in the low energies. However, the agree- medical sciences and astrophysics. Furthermore ment is excellent with that of Varella et al.[5] for such studies are crucial for the analysis of anti- the entire comparative energy range. hydrogen formation; testing of QED and CPT theorem. A thorough discussion on this can be found in the book written by Charlton and Hum- berston [1]. However, investigation on positron scattering fails to keep pace as compared to the case of its anti-particle electron. As such we have chosen the less attended methyl halides (CH3X, X=F, Cl, Br and I) as targets in the present calculations. These molecules yield majority of the inorganic free halogen radicals to the strato- sphere resulting in ozone depletion [2]. Further- more, these targets have vital biochemical and industrial uses. Figure 1. Total cross section for positron scatter- In the present calculations, we aim to pro- ing from methyl iodide vide a comprehensive set of cross sections for the methyl halide molecules. Spherical complex optical potential (SCOP) formalism is utilized References to compute elastic, inelastic and total scatter- ing cross sections. This formalism was origi- [1] Charlton and Humberston 2001 Positron Physics nally developed for electron scattering investi- Cambridge University Press gation which our group have modified for the [2] Eden et al. 2007 Chemical Physics 331 232-244 positron case [3]. The energy range chosen is from 1 eV to 5000 eV for the elastic and total [3] Singh et al. 2016 Journal of Physical Chemistry A120 5685 cross sections; however the inelastic cross sec- tions are calculated from the respective inelastic [4] Kimura et al. 2001 Journal of Physical Chemistry threshold. Figure 1 shows the total cross section 115 16 (Qtot) for positron-CH3I collision. We have also [5] Varella et al. 2013 J. Phys. B: At. Mol. Opt. Phys. depicted the inelastic cross section in the same 46 175202 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 98 ISAMP TC-7, 6 8 January, 2018, Tirupati CA044 Zainab − Energy levels and classified lines in the third spectrum of gold: Au III Aashna Zainab1 and Ahmad Tauheed2 Department of Physics, Aligarh Muslim University, Aligarh-202002 Topic: A (Spectrum of Au III) Abstract: The spectrum of doubly ionized gold configurations. The analysis of the 5d86p and (Au III) has been investigated in the wavelength 5d86s configuration is almost complete while region 450- 2100 Å, recorded on a 3 m and 10.7 70% of the levels in 5d76s6p configuration is m normal incidence vacuum spectrographs at still unknown. We therefore, are investigating Antigonish laboratory (Canada) and at NIST primarily this configuration and have (U.S.A.) respectively using triggered spark light established about 25 new energy levels based on source. The ground configuration of Au III is the identification of more than 100 spectral 5p65d9 and the regular excited configurations are lines. Hartree-Fock calculations involving the of the type 5d8nℓ. However, the core excited superposition of configurations were used to configurations are more complicated which predict the energy levels, wavelengths and includes 5p65d76s2, 5p65d76p2 in the even parity transition probabilities. Final interpretation of system and 5p65d76s6p, 5p55d10 and 5p55d96s in the results were made on the basis of least the odd parity system. squares fitted parametric calculations. Fairly This spectrum has been reported earlier good agreement has been found. by Wyart et al. [1]. They have studied the 5d86p, References 5d76s6p odd parity configurations and 5d9, [1] Wyart et al. 1996, Physica Scripta, 53, 174 5d8(6s+7s+6d) and 5d76s2 even parity ______ 1E-mail: [email protected] 2E-mail: [email protected] 99 ISAMP TC-7, 6 8 January, 2018, Tirupati CA045 Halder − Phase Space Structures and Isotope Separation of Bromine Molecules Suranjana Ghosh,1 Barun Halder,2 and Utpal Roy2 1Amity University, Rupaspur, Patna-801503 2 Indian Institute of Technology of Patna, Bihta, Patna-801103 Topic: A Localized quantum wave packet is the coherent sum of quantum states created by short, phase- controlled optical pulses [1]. A suitably prepared wave packet, more appropriately, a coherent state, is an ideal candidate to investigate the dynamics of the system through the time evolution, governed by a nonlinear energy function. Many applications in the literature emphasize on the autocorrelation function, which is an overlap of the initial wave packet with that after certain time. However, autocorrelation function does not satisfactorily reveal information regarding quantum interferences. Mesoscopic nonlocal superposition has become a prime tool towards quantum metrology in recent times [2]. Quantum interferences structures like sub-Planck-scale structures play very important role in this field of research. Here, we have used phase- 79 Figure 1. Autocorrelation functions for , Br2 (red, space analogy to distinguish two isotopes of deeper) and , 81Br (green, light) vibrational wave 79 81 2 Bromine molecule, Br2 and Br2, by utilizing a packets. The isotopes are shown to be separated after coherent state involving vibrational levels. 20ps. Due to the nonlinear energy spectrum of the Morse References potential, the wave packet shows interesting [1] I. Sh. Avermukh 1996 Phys. Rev.Lett. 77 17. phenomena like revivals and fractional revivals [2] J. R. Bhatt, P. K. Panigrahi, and M. Vyas 2008 during its course of evolution. Smallest interference Phys. Rev. A 78 034101. structures produced in phase space are known to be [3] S. Ghosh, A. Chiruvelli, J. Banerji, and P. K. the most sensitive to detect an infinitesimal external Panigrahi Phys. Rev. A 73 013411. [4] S. Ghosh, R. Sharma, U.Roy, P. K. Panigrahi, Phys. fluctuation or decoherence. We proposed a new Rev. A 92 053819. method of separating two isotopes of Bromine molecule at the shortest possible time, in the literature, to the author’s knowledge [3, 4]. This method is much more efficient than separating the isotopes by utilizing autocorrelation function. The [email protected], [email protected], [email protected] time of separation is considerably reduced, which is clearly demonstrated through Wigner phase-space picture. 100 ISAMP TC-7, 6 8 January, 2018, Tirupati CA046 Wajid − Isoelectronic Energy Levels of Xe-like Ions: La IV- Ce V Abdul Wajid 1, S. Jabeen , Abid Husain Department of Physics, AMU, Aligarh – 202002, Uttar Pradesh, India Topic: A. Quantum collisions and Spectroscopy of atoms, molecules, clusters and ions Three times ionized lanthanum (La IV) Fock method with relativistic correction using and four times ionized cerium (Ce V) have Cowan code, with inclusion of large number of Xenon-like structure and 5s25p6 is the ground interacting configurations. Energy levels values configuration of Xenon like ions. Excited of above mentioned configurations will be configurations 5s25p5 (nd+ns+nf+np+ng+nh+ni) presented. n>4 have been studied for the first three members of the Xenon isoelectronic sequence. In the present work our aim is to predict energy levels for 5s25p5 (5f+7d+8s+7p) configurations References 2 5 of La IV and 5s 5p (5f+7d+7s+7p) [1] Cowan, R. D., The Theory of Atomic Structure configurations of Ce V using the trend of and Spectra, (Univ. of Calif. Press 1981) and isoelectronic sequence. computer codes. [2] Kramida, A., Ralchenko, Yu., Reader, J., and We have also calculated energy levels of NIST ASD Team (2015). NIST Atomic Spectra 5s25p6,5s25p5 (4f + 5f + 6p + 5d + 6d + 7d + 7s Database (ver. 5.3), [Online]. + 8s) configurations theoretically by Hartree- 1 E-mail: [email protected] 101 Topic: A ISAMP TC-7, 6 8 January, 2018, Tirupati CA047 Mukund − Laser-induced fluorescence spectroscopy of jet-cooled LaNH: Observation of (0,0) C 2 푋 2+ transition Sheo Mukund 1, Soumen Bhattacharyya 2 and S.G. Nakhate 3 Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India Homi Bhabha National Institute, Bhabha Atomic Research Centre, Mumbai 400 085, India The Lanthanum imide (LaNH) molecules are produced in a pulsed supersonic molecular beam setup by the reaction of laser ablated Lanthanum metal plasma with 2% ammonia (NH3) seeded in helium. A (0,0) band of 2 2 + the C r 푋 system is observed by employing laser-induced fluorescence (LIF) spectroscopy. The 2 2 + 2 2 + rotationally resolved subbands, C 3/2 푋 and C 1/2 푋 are analyzed and molecular constants of the C state are determined by the unperturbed rotational lines. The laboratory spectra of LaNH molecule has Local rotational perturbations are observed been studied previously. In brief, the optical only in the f-parity levels of both substates of 1 1 2 Stark effect was measured for the 30 and 20 the C r state. However, the perturber state bands of the B X transition [1]. Later, the first could not be identified. It is speculated that the spectroscopic study of the à X and B X two perturber states may be of 2Σ+/ symmetry. systems was reported in the Ph.D. thesis of Scott J. Rixon [2]. The molecular constants for Table 1. Molecular constants (in cm-1) for the (000) 2 + 2 the X ground state were determined by vibrational level of the C r state of LaNH molecule 2 2 employing high-resolution spectroscopy. The Constants 퐶 1/2 퐶 3/2 bending and LaN stretching vibrational frequencies for the ground state were T 23093.259(4)a 23365.510(5) determined from dispersed fluorescence studies. B 0.273674(63) 0.27922(19) We report the LIF investigation of the (0,0) D 105 – -5.06(15) 7 band of the C (case a) X (case bS) transition of D 10 – -1.742(33) LaNH. p -0.0672(10) – LaNH molecules are produced by the reaction a Numbers in parentheses denote one standard of gas phase lanthanum atom with ammonia in deviation. laser vaporization pulsed free-jet apparatus [3]. Molecules in the beam were probed at right angle to the supersonic expansion axis by a tunable pulsed dye laser at resolution 0.06 cm-1 by using the angle tuned intra-cavity etalon facility available with the laser. The resulting LIF was dispersed by a monochromator and detected by a photo-multiplier tube. The resulting signal was integrated by a gated integrator and stored on a computer. Two intense bands centred at 23,366 and 23,093 cm-1 are identified as (0,0) band of 2 2 + 2 2 + C 3/2 푋 and C 1/2 푋 transitions. Figure 1. Rotationally resolved spectrum of the 2 2 + These bands are rotationally analyzed by fixing C 1/2 푿 transition in LaNH the rotational constants for the ground state to the values reported in Ref [2]. The molecular References constants for the Cstate are determined by least [1] Steimle et al. 2003 J. Chem. Phys. 118 1266 square fitting of wavenumber of the [2] S.J. Rixon. High resolution electronic spectra of unperturbed rotational lines using PGOPHER some new transition metal-bearing molecules. PhD program [4] and are given in Table 1. The Thesis, Department of Physics & Astronomy, 2 2 + experimental spectrum of C 1/2 푋 (0,0) University of British Columbia 2004. band along with simulated spectrum is shown in [3] Nakhate et al. 2010 JQSRT 111 394 Figure 1. [4] http://pgopher.chm.bris.ac.uk 1 [email protected] 2 [email protected] 102 3 [email protected] ISAMP TC-7, 6 8 January, 2018, Tirupati CA048 SinghJasmeet − Theoretical method to study electron-impact rotational excitation of molecular ions 1 Jasmeet Singh∗† , Marjan Khamesian† Viatcheslav Kokoouline† ∗ Department of Physics, Keshav Mahavidyalaya, University of Delhi, Delhi-110034, India. † Department of Physics, University of Central Florida, Orlando, FL-32816, USA. Topic: A In this study, cross sections and thermally- wide electron temperature range. averaged rate coefficients for electron-impact ro- tational transitions in HeH+ are computed [1] References for four lowest rotational levels of HeH+ using the UK R-matrix method combined [2, 3] to the [1] Marjan Khamesian Theoretical study of negative multichannel quantum defect theory (MQDT) molecular ions relevant to the interstellar and lab- oratory plasma, 2016, Ph. D. thesis, University of [4]. Here, we have applied channel elimina- Central Florida. tion procedure to evaluate more accurate results at low energy (< 0.01 eV). Scattering matrices [2] J. Tennyson, 2010 Phys. Rep. 491 29. for the process are generated using the UK R- [3] P. G. Burke 2011 R-Matrix Theory of Atomic Col- matrix method (Quantemol-N package) [5] and lisions: Application to Atomic, Molecular and Op- then used to compute rotational excitation cross tical Processes (Springer Series on Atomic, Op- sections for low energy region for different com- tical, and Plasma Physics) (Berlin, Heidelberg: Springer-Verlag). binations of initial and final rotational states of the target molecule. The approach is applied to [4] M. Aymar, C. H. Greene and E. Luc-Koening obtain cross sections for rotational excitation of 1996 Rev. Mod. Phys. 68 1015. + HCO . The thermally-averaged rate coefficients [5] J. Tennyson, D. B. Brown, J. J. Munro, I. Rozum, for this molecular processess are studied over a H. N. Varambhia, and N. Vinci. 2007 J. Phys. Conf. Series 86 012001. 1E-mail: [email protected] 103 ISAMP TC-7, 6 8 January, 2018, Tirupati CA050B Ram − Imaging electron-nuclear dynamics in strong field rescattering. N Bhargava Ram*1,2, S G Walt2, M Atala3, N I Shvestov-Shilovski4, A von Conta2, D Baykusheva2, M Lein4 and H J Worner2 1Department of Physics, IISER Bhopal, Bhopal, India 2Lab. For Physical Chemistry, ETH Zurich, Switzerland 3Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany 4Leibniz Universitat, Hannover, Germany Topic: A, B. Strong-field photoelectron holography and laser- induced electron diffraction are two powerful A similar analysis of the photoelectron images emerging methods for probing the ultrafast dynam- recorded around the first rotational revival, ics of molecules. However, both of them have so far where electronic and rotational dynamics take remained restricted to static systems and to nuclear place on similar time scales reveals the signa- dynamics induced by strong-field ionization. Here, ture of coupled electronic and nuclear dynamics we extend these promising methods to image purely (not shown). This observation suggests that electronic valence-shell dynamics in molecules us- time-resolved photoelectron holography may ing photoelectron holography [1]. Using impulsive offer a particularly sensitive probe of coupled stimulated Raman scattering by an intense non- electronic-nuclear dynamics in molecules, such resonant laser pulse, we simultaneously create a as those occurring at conical intersections. valence-shell electron wave packet consisting of the 21/2 and 23/2 electronic states of NO and a ro- tational wave packet that causes periodic alignment of the molecule. A second, time delayed laser pulse induces strong-field ionization, followed by veloc- ity-map imaging of the photoelectrons. References [1] S G Walt et al. , 2017 Nat. Commun. 8, 15651 Figure1. Holographic imaging of a molecular va- lence-shell-electron wave packet Fig 1 shows the characteristic signatures of strong- field photoelectron holography. Our analysis shows that the time-dependent photoelectron holography is particularly sensitive to the temporal evolution of the momentum-space wave function in the direction perpendicular to electron tunneling. 104 ISAMP TC-7, 6 8 January, 2018, Tirupati CA052 Uddin − Electron scattering total ionization cross section of H2CCCC: A cumulene car- bene detected in interstellar medium Nafees Uddin* 1, Pankaj Verma* 2 and Bobby Antony* 3 * Department of Applied Physics, IIT(ISM) Dhanbad, Dhanbad – 826004, Jharkhand, India Topic: A Cumulene carbenes, the H2Cn species com- 5000 eV . Total inelastic cross section is evalu- prising of double bonded long chain carbon ated using the well established Spherical backbone with terminal unbonded carbenes, are Complex Optical Potential (SCOP) formalism of immense astrophysical importance due to [5]. Total ionization cross section is estimated their presence in interstellar medium. The first from the total inelastic cross section using the three members of these interstellar molecules, Complex Scattering-Potential ionization H2CC, H2CCC and H2CCCC are highly polar contribution (CSP-ic) method [6]. isomers of acetylene, cyclopropenylidene and diacetylene respectively, which are non-polar molecules. Electron scattering studies of cu- mulene carbenes are of prime importance in References pursuit of the knowledge of unknown astro- physical phenomenon. [1]Killian T, Vrtilek J, Gottlieb C, Thaddeus P, Labora- tory detection of a second carbon chain carbene: In the present paper we report the total ioni- Butatrienylidene, H2CCCC. 1990 The Astrophysical zation cross section of Butatrienylidene Journal.;365:L89-L92. (H2CCCC), the third in the series of cumulene carbines. The first detection of this molecule in [2] Cernicharo J, Gottlieb C, Guelin M, Killian T, the laboratory was reported by Killian et al [1] Thaddeus P, Vrtilek J. Astronomical detection of and subsequently detected astronomically in the H2CCCC. 1991 The Astrophysical Jour- nal.;368:L43-L45. circumstellar shell of IRC +10216 by Cer- nichera et al [2] with IRAM 20m radiotele- [3] Kawaguchi K, Kaifu N, Ohishi M, Ishikawa S, scope. Kawaguchi et al [3] detected the pres- Hirahara Y, Yamamoto S. Observations of cumulene ence of Butatrienylidene in the dark TMC-1 carbenes, H2CCCC and H2CCC, in TMC-1. 1991 molecular cloud. Astronomical Society of Japan, Publications (ISSN 0004-6264).;43(4):607-619. The structure of H2CCCC as determined by Travers et al [4] is shown in Figure 1. [4] Travers M, Chen W, Novick S, Vrtilek J, Gottlieb C, Thaddeus P. Structure of the Cumulene Carbene Butatrienylidene: H2CCCC. 1996 Journal of Molecular Spectroscopy.;180(1):75-80. [5] R. Naghma, B.N. Mahato, M. Vinodkumar, and B.K. Antony, 2011 J. Phys. B 44 , 105204. [6] Antony B K, Joshipura K N and Mason N J 2004 Int. J. Mass Spectrom. 233 207 Figure 1. Structure of H2CCCC [4] In the present work, the total ionization cross sections (Qion) of H2CCCC on electron impact is calculated for incident energies (Ei) ranging from ionization threshold (I) of the target to 1E-mail: [email protected] 2 E-mail: [email protected] 3E-mail: [email protected] 105 ISAMP TC-7, 6 8 January, 2018, Tirupati CA053 Kadhane − Structural stability of polycyclic aromatic hydrocarbons and polycyclic nitrogen heterocycles under charged particle collisions 1 P. K. Najeeb∗ , M. V. Vinitha∗, A. Kala∗, P. Bhatt†, C. P. Safvan†, S. Vig‡ and U. 2 Kadhane∗ ∗ Department of Physics, Indian Institute of Space Science and Technology, Thiruvananthapuram, India †Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi, India ‡ Department of Earth and Space Sciences, Indian Institute of Space Science and Technology, Thiruvananthapuram, India Topic: A Polycyclic aromatic hydrocarbons (PAHs) line but nearly twice the yield in favor of iso- are a group of organic compounds consisting quinoline. The presence as well as the posi- of two or more fused aromatic rings. Poly- tion of nitrogen in PANHs have very little effect cyclic aromatic nitrogen heterocycles (PANHs) on the crosssection for capture as well as elec- are species with one or more CH groups sub- tron emission. The ratio of ionization to cap- stituted by a nitrogen atom in PAHs [1]. It is ture cross-section, as well as the ratio of dou- the proposed widespread existence of PAHs and ble ionization to capture ionization, are indepen- PANHs in the interstellar medium (ISM) that dent of the presence and position of Nitrogen in has largely driven recent investigations of their PAHs [Figure 1]. An attempt is made to correlate spectroscopic and photo physical attributes [2]. these observations with the various structure pa- Naphthalene(C10H8) is one of the smallest PAH, rameter obtained using structure calculations. but it exhibits many general spectroscopic and 100 (a) Quinoline ( C H N ) structural properties of larger PAHs [3] and 9 7 Naphthalene ( C H ) 10 8 hence is a good test candidate for PAHs. Small Isoquinoline ( C H N ) 9 7 PANHs like quinoline(C9H7N) and its isomer c i isoquinoline(C9H7N) readily dissociate under ex- 10 posure to interstellar radiation and thus an in- 100 terest in their photochemistry, as they produce (b) reactive photo products that may contribute to the composition of the ISM [4]. Particularly of ci 10 significance is the HCN loss mechanism in these ee systems. The main focus of the present work is to compare fragmentation process under ener- 1 40 60 80 100 120 140 160 getic charged particle interaction on naphthalene Proton beam energy (keV) with its nitrogen derivatives. Figure 1. The ratio of partial crosection Generally for PAHs and PANHs, the loss of for (a) ionisation (σi) to capture (σc) (b) dou- H and C2H2/HCN are the most dominant sta- ble ionisation (σee) to capture ionisation (σci) for tistical dissociation channels. Astro-biologically naphthalene (C10H8) quinoline (C9H7N) isoquino- important statistical dissociation channels of the line (C9H7N) with different proton beam energies naphthalene and its nitrogen containing deriva- tives are probed using time of flight mass spec- References trometry technique (ToF). On the basis of pro- jectile beam energy dependence of the yield, the [1] S. B. Charnley et al. 2005 Advances in Space Re- effect of plasmon excitation in quinoline and iso- search 36 137 quinoline is shown for the first time. A strong [2] A. G. Tielens. 2008 Annu. Rev. Astron. Astro- dependence of the statistical dissociation yield phys. 46 289 on the location of nitrogen atom in the two molecules is observed and the decay time evo- [3] E. Ruehl et al. 1989 The Journal of Physical lution was found to be exactly same for the same Chemistry 93 17 channels. A detailed analysis of HCN loss showed [4] Mishra P M, Rajput J, Safvan C P, Vig S and identical time scales in quinoline and isoquino- Kadhane U 2013 Physical Review A 88 052707 1E-mail: [email protected] 2E-mail: [email protected] 106 ISAMP TC-7, 6 8 January, 2018, Tirupati CA054 Kadhane − Collisional isomerisation between naphthalene and azulene due to energetic proton Vinitha M V 1, †,Najeeb P K1,Anudit K1, P. Bhat2, C P Safvan2, S Vig3, U kadhane1,* 1Department of Physics, Indian Institute of Space Science and Technology, Thiruvanthapuram, India, 2Inter-University Accelerator Centre, Aruna Asif Ali Marg, New Delhi, India 3Department of Earth and Space science, Indian Institute of Space Science and Technology, Thiruvananthapuram, India Topic:A Polycyclic aromatic hydrocarbons (PAHs) projectile as trigger to start data acquisition and are popular for their collective excitation. the data is recording in list mode to preserve the Astronomical and terrestrial relevance of multi coincidence information. PAHs have resulted intense study of their structure and dynamics in the last couple of Single and double ionisation and subsequent decades. PAHs, irrespective of their complex neutral loss processes in electron emission and electron capture modes have been studied in structure show unusual resilience in harsh detail for naphthalene and its isomer azulene at radiations. Structural stability, dynamics and intermediate proton velocities. Relative yields rearrangement of this class of molecules can of C2H2 loss as a function of proton energy, in be explored using charged particle as the direct and capture ionisation processes for both projectile and separating the statistical and PAHs is shown in figure1.Quantitative non-statistical decay channels. It is instructive exercises have been carried out to explain the the study of proton impact collisions for small energy loss processes causing ionisation and PAHs at intermediate velocities which will neutral evaporation for both the isomers in the help in understanding how low energy cosmic proton energy regime discussed here. Azulene rays can interact with PAHs in interstellar being isomer of naphthalene, the isomerisation medium. These studies help in understanding dynamics have become the key interest of the energetics of ion-PAH collision as well as post study. collisional relaxation mechanisms. The onset of H, 2H/H2 and C2H2 loss studies for proton- naphthalene collision is investigated by this group in past [1]. The experiment was carried out at the Low Energy Ion Beam Facility, IUAC, Delhi. A ToF Mass Spectrometer with a position sensitive MCP detector is used to detect the recoil ions after interaction with the proton beam. We used proton beam at different energies (Energy ranges from 50keV-200keV). The target vapour was send to interaction chamber via a fine needle. The recoil ion gets extracted to the + Figure 1. Normalised C2H2 loss from C10H8 for electron negative potential on top while the electron gets emission and electron capture modes in naphthalene and extracted to positive potential below. During azulene. the interaction it may happen that the projectile proton may capture an electron from the Reference molecule. This neutral can be detected by [1] P M Misra,J Rajput,C P Safvan,S Vig and another channeltron downstream. Since this is a continuous beam, we take electron or neutral U Khadhane,2013,J.Phy.Rev.A,88,052707. *[email protected] 107 ISAMP TC-7, 6 8 January, 2018, Tirupati CA055 Madugula − Two- and three-body dissociation dynamics of H2O2 M. Nrisimhamurty 1, L. C. Tribedi, D. Misra 2 Department of Nuclear and Atomic Physics Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai-400005, INDIA 8+ Topic: A. To investigate the ion-induced dissociation dynamics of H2O2 in collisions with 1 MeV Ar ions. Interaction of atoms and molecules by ener- tained from the electron cyclotron resonance ion getic highly-charged ions is of utmost importance accelerator (ECRIA) at TIFR, Mumbai. Elec- to explore the structure of matter. However, trons that are created during the fragmentation these studies remained as a challenging task for do serve as a start signal. Recoil ions produced a brief period due to the many-body nature of are projected onto a position- and time-sensitive atoms/ molecules and complexity involved dur- detector [5]. From the coincidence observations, ing ion-induced breakup. But this field of re- we found two dissociation channels for two-body + search (particularly, ion-induced fragmentation decay of H2O2 whereas H2O2 fragments into H , + + dynamics) gained momentum from last couple of H and O2 in a three-body dissociation process. decades after the invention of the state-of-the-art Interestingly, a signature of angular anisotropy recoil-ion momentum spectroscopy (RIMS) [1]. is observed as shown in the Fig. 1, which may This technique is highly robust in obtaining be an outcome of post-collisional effects. kinematically-complete information about the various reaction pathways involved, in terms of kinetic energy release, momentum distributions and angular correlations. Not only that, RIMS also set a benchmark which lead to the devel- opment of next generation theoretical method- ologies to unravel the ion-induced dissociation dynamics. Though today, ion-impact breakup dynamics of a large no. of di- and tri-atomic molecules have been rigorously studied but in- formation about polyatomic molecules is yet to be explored. Thus, this motivated us to work and report about the ion-induced dissociation studies of one such polyatomic molecule, H2O2. Hydrogen peroxide (H2O2), a non-planar Figure 1. Angle between the individual momen- molecule, is of basic interest here due to its rel- tum vectors and beam direction for the disso- evance in understanding the chemistry of ozone. 2+ + + ciation channel H2O2 H +O2H . Solid −→ + + It along with HCHO and OHn, has been identi- and dashed line corresponds to H and O2H fied to be playing a decisive role in the behav- fragments, respectively. The dotted curve corre- ior of oxidation power and self-cleaning capacity sponds to isotropic distribution (sinθ). Inset shows of the atmosphere [2,3]. In addition, recently it “dN/d(cosθ)” behaviour against various angles. has been discovered in the interstellar medium [4] and proved to be a prominent molecule to be studied to understand the radiation damage of References biological matter [2]. Although the above factors [1] J. Ullrich et al. 1997 J. Phys. B 30 2917 highly-demands kinematically-complete informa- tion about H2O2, it being unstable in ambient [2] D. Nandi et al. 2003 Chem. Phys. Lett. 373 454 conditions resulted in the availability of very few [3] T. Klippel et al. 2011 Atmos. Chem. Phys. 11 details about its structure and dynamics. Hence, 4391 present observations on dissociation dynamics of [4] F. Du et al. 2012 Astron. Astrophys. 538 A91 H2O2 are of paramount importance. In the present work, 1 MeV Ar8+ ions are ob- [5] A. Khan et al. 2015 Rev. Sci. Instrum. 86 043105 1E-mail: [email protected] 2E-mail: [email protected] 108 ISAMP TC-7, 6 8 January, 2018, Tirupati CB001 Banerjee − Effects of interchannel coupling on angular distribution of photoelectrons and on time delay in the autoionization regions of Neon 2s np resonance series → 1 2 ,#3 S. Banerjee∗ , H. R. Varma‡ , & P. C. Deshmukh† ∗ Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India ‡ School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, H.P. 175005, India † Department of Physics, Indian Institute of Technology Tirupati, Tirupati, 517506, India # Department of Physics, Indian Institute of Science Education and Research, Tirupati, 517507, India Topic: B. Wigner time delay in collisions and photoionization Autoionization in atomic physics is a very interesting topic in the area of research for all the time. Autoionization resonance occurs due to the interference of bound to bound and bound to continuum transitions at certain energy ranges. The electron correlations play a vital role particularly in these regions. Among the vari- ous observables that depend on phase, angular asymmetry parameter (β) is important one to study [1]. It also shows dependence on electronic correlation. Time, on the other hand, is not an observable in quantum mechanics, but time de- lay [2,3] in photoionization can be measured [4]. Our study aims to look at the variation of β and Figure 1. Angular asymmetry and WES time de- the time delay (τ) in Neon 2s np resonance → lay in vicinity of 2s 4p resonance series. We employ relativistic random phase ap- → proximation (RRPA) [5] and relativistic multi- channel quantum defect theory (RMQDT) [6] for present calculations. We have used two different References levels of interchannel coupling to find out the de- [1] T. Banerjee et al. 2007 Phys. Rev. A 75(4), pendence of the aforementioned observables on 042701 electronic correlations. The figure shows that, β [2] E. P. Wigner 1955 Phys. Rev. 98(1), 145 remains qualitatively the same, while time delay goes from only positive to a combination of pos- [3] L. Eisenbud 1948 Ph. D.(Doctoral dissertation, itive and negative values when we coupled more thesis Princeton University) channels for calculation. There are discussions [4] S. Saha et al. 2014 Phys. Rev. A 90(5), 053406 on the behaviour of time delay near resonance [5] W. R. Johnson and C. D. Lin 1979 Phys. Rev. A region using a generalized expression [7] for time 20(3), 964 delay in terms of Fano parameters [8]. [6] C. M. Lee and W. R. Johnson 1980 Phys. Rev. A 22(3), 979 [7] P. C. Deshmukh et al. 2017 (private communica- tion) [8] U. Fano 1961 Phys. Rev. 124(6), 1866 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 109 ISAMP TC-7, 6 8 January, 2018, Tirupati CB002E Jain − Attosecond-Streaking Spectroscopy on a Liquid-Water Microjet A. Jain1, R. Heider2, M. Wagner2, A. Duensing2, T. Gaumnitz1, I. Jordan1, J. Ma1, J. Riemensberger2, M. Mittermair2, W. Helml2, R. Kienberger2, H. J. Wörner1 1. Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland 2. Physik-Department, Technische Universität München, James-Franck-Str. 1, D-85748, Garching, Deutschland Topic: B, E Abstract: Attosecond-streaking experiments on gas- and liquid-phase water employing the liquid microjet are pre- sented. The streaking traces are used to extract delays between the inner- and outer-valence states, giving access to the attosecond dynamics of photoionization, transport and scattering processes in water. I. Introduction III. Results Attosecond-streaking spectroscopy1, has given The measurements on gas-phase water molecules real-time access to photoionization delays of atoms provide effective photoionization delays between in the gas phase2, and the additional effects of elec- the outer- (1b1, 3a1, 1b2) and inner-valence (2a1) tron transport processes through atomic layers and shells. These delays contain information on pho- interfaces of solid-state systems3,4. Here, we report toionization dynamics of the molecule and, possi- on the first attosecond-streaking experiments on bly, electron-correlation phenomena that are known liquid samples. We have realized as-streaking pho- to play a role in inner-valence ionization. For case toelectron spectroscopy on water in the gas and liq- 5. of liquid-water, using the spectrogram fitting tech- uid phases using a liquid microjet nique2,3, we obtain a delay of ~16 as between pho- II. Experimental Method toelectrons emitted from the inner- and outer- A carrier-envelope-phase-stabilized (~200 mrad valence shell. Measurements on liquid water addi- rms), sub-5 fs, Ti:Sapphire laser system (4 kHz, 1.2 tionally provide insight into transport of electrons mJ, 790 nm) is used to generate isolated attosecond through liquid water on the attosecond time scale, pulses by intensity gating, centered at 90 eV (~5 eV including elastic and inelastic scattering of electrons FWHM, 455 as Fourier transform-limited). The with liquid-phase water molecules. residual NIR and the generated as-XUV pulses are focused by a two-component mirror assembly onto the liquid microjet (25 µm diameter). Scanning the delay between the XUV pump and the NIR streak- ing pulse with a linear piezo stage allows us to measure time-dependent photoelectron spectra by means of a field-free time-of-flight (TOF) spec- trometer. Successive measurements on gas-phase water evaporating from the liquid microjet and from liquid water inside the microjet are performed by translating the jet in and out of the laser focus. Figure 2. Photoelectron spectra from liquid-phase water: measured using synchrotron radiation7, (blue), convolut- ed with 5 eV Gaussian corresponding to inner-mirror reflectivity (red) and measured spectra with isolated atto- second pulses at 90 eV (yellow). References [1] F. Krausz, M. Ivanov, Rev. Mod. Phys., 81,163 (2009). [2] M. Schultze et al., Science, 328, 1658 (2010). [3] S. Neppl et al., Nature, 517, 342(2015). [4] R. Locher et al, Optica, 2, 405 (2015). [5] B. Winter, M. Faubel, Chem. Rev., 106, 1176 (2006). Figure 1. (a) Measured and (b) Reconstructed streaking trace in liquid-phase water with isolated attosecond puls- [6] I. Jordan et al., Rev. Sci. Instrum., 86, 123905 (2015). es at 90 eV giving a delay of ~16 as between inner- and [7] B. Winter et al., J. Phys. Chem. A, 108, 2625 (2004). outer-valence shell. E-mail: [email protected] 110 ISAMP TC-7, 6 8 January, 2018, Tirupati CB004 Banerjee − Photoionization dynamics of Ar@C540 1 2 3 ,#4 Sourav Banerjee∗ , Afsal Thuppilakkadan‡ , H. R. Varma‡ , & P. C. Deshmukh† ∗ Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India ‡ School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, H.P. 175005, India † Department of Physics, Indian Institute of Technology Tirupati, Tirupati, 517506, India # Department of Physics, Indian Institute of Science Education and Research, Tirupati, 517507, India Topic: B. Wigner time delay in collisions and photoionization Fullerenes, which are nanostructure forma- ference, the RRPA calculations are further car- tions of carbon atoms, have attracted intense re- ried out in its non-relativistic limit(NRL-RRPA) search activities. A variety of fullerenes exist in so that it can mimic the non-relativistic results. nature with varying number of carbon atoms. An The results from NRL-RRPA also show oscilla- atom can be trapped inside the hollow space of tions with smaller amplitude as in the case of these systems and this external cage can bring RRPA. The work can be extended to study pho- significant modifications in the properties of the toionization dynamics for different cage parame- atom. An outstanding feature of the photoion- ters. ization spectrum of such confined atoms [1] is the presence of confinement oscillations due to the interference between the directly ionized elec- tron wave and its reflected component from the cage. A number of studies have been reported on atoms trapped in fullerenes (A@Cn), where n denotes the number of carbon atoms present [1]. In this work, we report photoionization studies of argon atom encaged in a C540 giant fullerene (Ar@C540). The presence of C540 is modeled by a spherical attractive well with the atom at its center. The cage has been modelled by a spher- ical potential of depth (U0)= 0.441 a.u., thick- Figure 1. Photoionization cross section for ness (∆)= 1.9 a.u. with inner radius (r0)= 18.85 a.u. [1]. It is to be noted that, the assumption Ar@C540 in different schemes that the atom at the center is not fully realistic Recently photoionization studies in the time because of the big size of C540. The exact level domain have emerged as intense research areas of displacement from the center is not precisely in atomic physics [3]. The present work also known. The present studies can be considered as aims at studying the role of non-dipole interac- the zeroth approximation of the cage and it can tions in the dynamics of 1s photoionization. The provide useful information to understand pho- confinement oscillations are also expected in the toionization dynamics of other complex types of quadrupole channels and it is of great interest endohedral systems such as A@C @C @C study the modification on time delay engendered 60 240 540 by the confinement oscillations in Ar@C . where it is reasonable to assume the atom at its 540 center. Here, we employ relativistic random phase ap- References proximation (RRPA) methodology which in- [1] V. K. Dolmatov et al. 2004 Rad. Phys. and Chem. cludes many electron correlation and relativistic 70(1), 417-433 effects. In Figure 1, we show the 1s cross sec- [2] V. K. Dolmatov et al. 2008 Phys. Rev. A 78(1), tion of Ar@C540. It is found that amplitude of the confinement oscillations are much smaller in 013415 RRPA compared to an earlier reported Hartree- [3] P. C. Deshmukh et al. 2014 Phys. Rev. A 89(5), Fock results [2]. In order to understand the dif- 053424 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 4E-mail: [email protected] 111 ISAMP TC-7, 6 8 January, 2018, Tirupati CB006 Saha − Shape resonance induced Wigner time delay in atomic photoeffects S.Saha* 1, J.Jose† 2 and P.C. Deshmukh$, # 3 * Department of Physics, IIT Madras, Chennai – 600036, Tamil Nadu, India † Department of Physics, IIT Patna, Bihta – 801103, Bihar, India $ Department of Physics, IIT Tirupati, Tirupati – 517506, Andhra Pradesh, India # Department of Physics, IISER Tirupati, Tirupati – 517507, Andhra Pradesh, India Topic: B Wigner time delay [1] studies in the case of resonance. The sharp change in the phase in all negative ion phodetachment were reported three channels causes significant time delay for relativistically split dipole channels near the threshold region in all three channels. originating from the 3p subshells of Cl- [2] The present study enables the determination of and the 4d subshells of Tm- [2, 3] earlier. The outgoing photoelectron in the the resonance energy where the phase change photodetachment process [4] escapes in the is most rapid in the broad resonance region. field of the neutral residual atom and thus 100 150 200 250 300 350 6 doesn’t contain the large Coulomb 3d 3p 0.6 3/2 3/2 3p 3d 1/2 5/2 component in its phase. That helps in 0.5 - 5 0.4 Br studying the Wigner time delay, emerged 4 0.3 ( 3d ->f 3 solely due to the centrifugal barrier shape 0.2 3/2 5/2 3d ->f 5/2 5/2 0.1 2 resonance [5]. In the shape resonance Phase 3d ->f 5/2 7/2 0.0 Cross(Mb) section region, one expects the phase to change Cross sec3d5/2+3d3/2 1 -0.1 rapidly and thereby cause significant time -0.2 0 100 150 200 250 300 350 delay, according to Wigner-Eisenbud Photon energy (eV) formalism [1, 6]. However, in the case of photoionization studies, this Figure 1. Photodetachment phases for all three phenomenology is obliterated [2] by the relativistically split nd→εf channels and total 3d - large Coulomb phase. In the present work cross section of Br we investigate the amplitude, phase and 3d 3d 5/2 3/2 time delay for all the relativistically split 400 3d ->f 3/2 5/2 nd→εf channels in the photodetachment of - 3d ->f - Br 5/2 5/2 200 3d ->f Br and in the photoionization of atomic Kr 5/2 7/2 (isoelectronic to Br-) and for all the three 0 relativistically split nd→εf channels and Timedelay (as) nf→εg channels in the photodetachment of -200 - 76 77 78 79 80 Au and in the photoionization of atomic Photon energy (eV) - Hg (isoelectronic to Au ) using the relativistic random phase approximation Figure 2. Photodetachment time delays for all three (RRPA) [7]. This comparative study will relativistically split nd→εf channels of Br- help us to demonstrate the suppression of the centrifugal barrier shape resonance References: effects in photoionization process. In Fig. 1, photodetachment phases for all the three [1] E. P. Wigner 1955 Phys. Rev. 98 145 relativistically split nd→εf channels of Br- [2] S. Saha et al 2016 BAPS 61(8) 53 (left y-axis) and the total 3d cross section [3] S. Saha et al 2017 BAPS 62(8) 137 [4] V. K. Ivanov 1999 J. Phys. B 32 R67 (right y-axis) are shown. The time delay [5] A. R. P. Rau and U. Fano 1968 Phys. Rev. 167 has been displayed in Fig. 2 for all the 7 three relativistically split nd→εf channels. [6] L. E. Eisenbud 1948 Ph. D. thesis, Princeton The cross section goes through the delayed Univ. maximum indicating the presence of shape [7] W. R. Johnson and C.D. Lin 1979 Phys. Rev. A 20 964 1 E-mail: [email protected] 2 E-mail: [email protected] 3 E-mail: [email protected] 112 ISAMP TC-7, 6 8 January, 2018, Tirupati CB007 Saha − Influence of SOIAIC in photodetachment and photoionization time delays near the centrifugal barrier shape resonance S.Saha* 1, J.Jose† 2 and P.C. Deshmukh$, # 3 * Department of Physics, IIT Madras, Chennai – 600036, Tamil Nadu, India † Department of Physics, IIT Patna, Bihta – 801103, Bihar, India $ Department of Physics, IIT Tirupati, Tirupati – 517506, Andhra Pradesh, India # Department of Physics, IISER Tirupati, Tirupati – 517507, Andhra Pradesh, India Topic: B Effects of spin orbit interaction activated 200 4d 4d L1a: 4d5/2->f7/2 inter-channel coupling (SOIAIC) [1, 2] on 5/2 3/2 I- 150 L1a: 4d5/2->f5/2 L1b: 4d3/2->f5/2 photoionization parameters were studied in 100 L2: 4d5/2->f7/2 L2: 4d5/2->f5/2 an earlier work [3] in our group. SOIAIC 50 L2: 4d3/2->f5/2 effects were seen in the dipole cross 0 sections of Xe 4d and Rn 5d subshells. -50 Timedelay (as) Here, we report how SOIAIC affects the -100 -150 Wigner time delay [4] in photoeffect. Time 40 60 80 100 120 140 delay has been calculated for all the Photon energy (eV) relativistically split ndεf channels in the photodetachment of I- and also in the Figure 1. Time delays are shown for all the three photoionization of atomic Xe using the relativistically split ndεf channels in - relativistic random phase approximation photodetachment of I using dashed (L1) and solid (RRPA) [5]. This comparative study will (L2) lines. Different colours correspond to different also help us in understanding the time transitions. delay associated with the two processes. In the case of photodetachment, the time 500 4d Xe delay occurs solely due to the centrifugal 5/2 400 L1a: 4d ->f 5/2 7/2 L1a: 4d ->f barrier shape resonance [6]. Whereas in the 5/2 5/2 300 L1b: 4d ->f 3/2 5/2 case of photoionization, the large Coulomb L2: 4d ->f 200 5/2 7/2 L2: 4d ->f phase governs the time delay near the 5/2 5/2 100 L2: 4d ->f 3/2 5/2 threshold. Calculations have been (as) delay Time 4d performed at select levels of truncation in 0 3/2 -100 the RRPA: (Level L1) Pseudo-Independent 60 80 100 120 140 Particle Truncation (PIPT): At this level of Photon energy (eV) truncation, we exclude SOIAIC by including channels only from j= l+1/2 Figure 2. photoionization time delays are shown subshell (Case L1a) or from j= l-1/2 (Case for all the three relativistically split ndεf channels L1b) subshell; (Level L2) Intra-Subshell in photoionization of Xe using dashed (L1) and Truncation (ISST): here, we include solid (L2) lines. Different colours correspond to SOIAIC by coupling the channels arising different transitions. from both the subshells j=l±1/2 of the spin- orbit doublet. In Figure 1 and Figure 2 the References: photodetachment time delay for ndεf transition in I- and photoionization time [1] A. Kivimäki et al 2000 Phys. Rev. A 63 012716 delay for ndεf transition in Xe are plotted [2] M. Ya. Amusia et al 2002 Phys. Rev. Lett. 88 respectively at the above mentioned levels 093002 [3] S. Sunil Kumar et al 2009 Phys. Rev. A 79 of truncation. The influence of SOIAIC 043401 affects the time delay near the threshold [4] E. P. Wigner 1955 Phys. Rev. 98 145 region in both the cases. [5] W. R. Johnson and C.D. Lin 1979 Phys. Rev. A 20 964 1 E-mail: [email protected] [6] A. R. P. Rau and U. Fano 1968 Phys. Rev. 167 2 E-mail: [email protected] 7 3 E-mail: [email protected] 113 ISAMP TC-7, 6 8 January, 2018, Tirupati CB008 Thuppilakkadan − Effect of model potentials (smooth Vs hard) on the Wigner time delay of H@C60 Photoionization 1 Afsal Thuppilakkadan∗ , Subhasish Saha† Jobin Jose† Hari R. Varma∗ ∗ School of Basic Sciences, IIT Mandi, Mandi – 175005, Himachal Pradesh, India † Department of Physics, IIT Patna, Bihta– 801103, Bihar, India Topic: B Understanding photoionization dynamics in the time domain has been a subject of, both experimental and theoretical, immense research activities in recent years [1]. Studies of Wigner- Eisenbud-Smith time delay(tWES) associated with the photoionizaton [2] channels leads to deeper understanding of the role of correlation and relativistic interactions present in the sys- tem. A number of studies on atoms focussing the region of Cooper minimum are already reported [3,4]. Time delay studies of endohedral atoms are of Figure 1. Phase shift and time delay in photoion- great interest because of the presence of con- ization of H@C60 employing ASW and GASW po- finement oscillations in their ionization channels. tential Such studies of tWES in the resonance region provide a better understanding of the dynamics Figure 1 shows a comparison of time delay and of photoionization of confined atomic systems phase shift associated with the 1s p pho- [5,6]. These previous studies used an annular toionization obtianed by employing→ ASW and square well potential (VASW ) to simulate the GASW potentials with depth of the well as 1.03 confining environment which is described below: au. Phase shift in photoionization is determined by referring to the asymptotic behavior of ra- dial part of the wave-function obtained numer- U, if rc 42 r rc + 42 VASW (r) = − − ≤ ≤ ically. Both time delay and phase shift show ( 0, otherwise, confinement oscillations. However, amplitude of where r is the center of confinement cage and confinement oscillations is significantly reduced c 4 is its width. This model has unrealistic disconti- when GASW potential is used in the calcula- tion near the threshold. A detailed analysis will nuities (hard) at the shell boundaries. However, be presented by studying this system for differ- earlier it was shown that photoionization cross ent depths of confining potentials. We will also section calculated by employing a smooth poten- present alternate analytical calculation to sub- tial do not differ much compared to the cross stantiate the numerical results obtained. section obtained by VASW [7]. Here, we use a model jellium potential termed Gaussian annu- References lar square well (VGASW ) model, described below, to investigate cross-section, phase shift and time [1] Pazourek et al. 2015 Rev.mod.phy. 87 765 delay in the photoionization of the confined H [2] M. Schultze et al. 2010 Science 328 1658 atom (H@C ). 60 [3] A. S. Kheifets 2013 Phys. Rev. A 87 063404 r rc 2 A ( − ) VGASW (r) = e− √2σ + VASW . [4] Saha S et al. 2014 Phys. Rev. A 90 053406 √2πσ [5] P. C. Deshmukh et al. 2014 Phys. Rev. A 89 This model simulate both the qualitative and 053424 quantitative nature of the potential employed [6] A Kumar et al. 2016 Phys. Rev. A 94 043401 by Puska and Nieminen [8]. A comparison is made between the results obtained by em- [7] V. K. Dolmatov et al. 2012 J. Phys. B 45 105102 ploying ASW and GASW model potentials. [8] M. J. Puska et al. 1993 Phys. Rev. A 47 1181 1E-mail: afsal [email protected] 114 ISAMP TC-7, 6 8 January, 2018, Tirupati CC002 Bhushan − A Two Dimensional Magneto Optical Trap with High and Tunable Optical Depth for Slow Light Applications Sumit Bhushan and Raghavan K Easwaran Department of Physics, IIT Patna, Bihta, Patna- 801103, Bihar, India Topic: C The storage of light pulses inside a medium is vital for applications such as quantum infor- mation, quantum communication, and quantum computing [1]. This storage is facilitated by media which are capable of slowing down the group velocity vg of light to extremely small values. The most commonly used method to realize such storage is Electromagnetically In- duced Transparency (EIT) which makes a me- dium transparent to a resonant light and simul- taneously reduces the group velocity of light by 7 or more orders of magnitude, thereby making the storage of these light pulses possible [2]. Out of the many media in which such storage has been demonstrated, cold atomic medium in a two dimensional magneto optical trap (2D- Figure 1. Side view of our proposed design MOT) has the most distinct advantages like high Optical Depth (OD), high efficiency of storage, and high Delay Bandwidth Product (DBP). Here, we are presenting design of a 2D- MOT with very high and tunable OD resulting in very small group velocity. Our design can be divided into three main parts, (a) vacuum chamber design, (b) magnetic coil design, and (c) the laser system. The vacuum assembly con- Figure 2. Current carrying rectangular coils in anti- sists of a source chamber and a science cham- Helmhotz configuration. CL denotes cooling lasers. ber. As shown in Fig. 1, the source chamber has a glass opening through which the probe and The number density NA of trapped atoms in pump beams constituting the EIT set up are in- our design is 2.3 x 1011 atoms/cm3. OD obtained jected into the medium. 87Rb atoms are sent into in our design is 1374 resulting in a group veloc- the source chamber through an inlet on the top ity of 1.4 m/s. The DBP is 163 and hence the of it and are trapped by cooling and trapping number of pulses that can be stored with our lasers in the science chamber along a line of design is 29 which is very high when compared length L2D = 8cm where the magnetic field is to other slow light systems. zero because of the anti-Helmholtz rectangular coils as shown in Fig. 2. The cooling lasers References (CL) shown in Fig. 2 are rectangular sheet [1] Afzelius M et al. 2015 Phys. Today 68 42 beams with dimensions 80mm x 10mm and are [2] Hau L V et al. 1999 Nature 397 594 slightly red detuned from the D2 transition of [3] Bhushan S and Easwaran R K 2017 Appl. Opt. 87 Rb atoms. 56 3817 E-mail: [email protected] E-mail: [email protected] 115 ISAMP TC-7, 6 8 January, 2018, Tirupati CC003 Das − Quantum State Transfer through Coherent Atom-Molecule Conversion in Bose- Einstein Condensate Subhrajit Modak*, Priyam Das†, 1 and Prasanta K. Panigrahi* * Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal - 741246, India † Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi - 110016, India Topic: C - Laser cooling, Bose-Einstein Condensates, Atomic clocks, and Quantum computing. Abstract: We demonstrate complete quantum state transfer of an atomic BoseEinstein con- densate to molecular condensate, mediated by solitonic excitations in a cigar shaped mean- field geometry. Starting with a localized soli- tonic atomic condensate, we show compatible gray solitonic configuration in the molecular condensate, which results in complete atom- molecule conversion. The effect of inter and intra-species interactions on the formation of molecular condensate is explicated in the pres- ence of Raman Photoassociation. It is found that Photoassociation plays a crucial role in the co- herent atom-molecule conversion as well as in the soliton dynamics. The gray soliton disper- sion reveals bi-stable behavior, showing a re- entrant phase in a physically accessible para- metric domain. Figure 3. (a) Shows dispersion relation of molecular condensate for different values of α, revealing a degener- Figure 1. Schematic diagram of the atomic- acy in molecular energy for higher values of α. (b) de- molecular configuration, where atomic density is de- picts the variation of molecular energy as a function of scribed by the bright soliton and molecular profile the inter-conversion and Mach angle. The periodic nature possesses gray soliton. The strength of the inter at- of energy clearly shows the coherent nature of atom- om-molecular transfer is responsible for a complete molecule inter-conversion. Here parameter values are state transfer from atomic to molecular BECs. same as that in Fig. (2). References [1] S. Modak, Priyam Das and P. K. Panigrahi 2017 arXiv: 1708.04286. [2] D. J. Heinzen et. al., 2000 Phys. Rev. Lett. 84, 5029. [3] F. Richter et. al. 2015 New J. Phys. 17, Figure 2. Depiction of the density profiles of atomic 055005. and molecular wave packets. (a) shows the propaga- tion of bright soliton in the atomic condensate to that of gray soliton in the molecular condensate in (b). E-mail: [email protected] 116 ISAMP TC-7, 6 8 January, 2018, Tirupati CC005 Batin − Breathing Dynamics of Ultracold Atoms in a Vibrated Optical Lattice Jayanta Bera1,a, A. Q. Batin1, Suranjana Ghosh2, Utpal Roy1,b 1 Indian Institute of Technology of Patna, Bihta, Patna, Bihar- 801103 2 Amity University Patna, Rupaspur, Patna, Bihar-801503 Topic: C Ultracold quantum gas is known to be very robust, In addition to the number of numerical studies in the highly tunable and versatile system, which has literature, this analytical approach will provide a clear recently found numerous interesting applications correlation of the available frequencies in the towards quantum optics, quantum information, weak dynamics with the trap parameters, which will bring measurement, higher harmonic generation etc. Bose- out potential applications towards precise Einstein Condensate (BEC) in a harmonic trap is a experimentations to detect fluctuations of various well known situation and the advent of highly physical quantities like, thermal fluctuations, field controllable laser techniques helped physicists to variation etc. bring out new phenomena in BEC in presence of tunable optical lattices (OL) [1-3]. A large number of experimental works have been carried out in the literature. Analytical and numerical investigations on BEC have also got huge emphasize to have a clear understanding of the dynamics under various trap- geometry and non-linear parameter modulation in 1D, 2D and 3D [4]. The nonlinear Gross-Pitäevskii equation (GPE) is most appropriate to study the Fig. (1) : Oscillation of the width with time in dynamics of BEC in weak nonlinear interaction. The presence of HOL trap and with modulation solution of the GPE is a difficult task even in lower oscillation frequency(ω)=0.8π. All the parameters are dimensions. There are few analytical methods for dimensionless. some well known potential profiles. Analytical variational approach is also one of the useful methods to study the dynamics of GPE [6,7]. In this work, we analytically study the 1D dynamics of BEC in the presence of harmonic plus optical lattices (HOL) potential using variariational approach. We mainly concentrate on the variation of the width of the condensate density with time, where the depth of the OL has a sinusoidal temporal Fig. (2) : Frequency plane of the time-evolution modulation. As a result, the change in the width of depicted in fig. (1). The amplitudes of the SBFs the condensate due to the harmonic trap is modulated depend on the amplitude of the modulation parameter by an overall oscillation coming from the amplitude of OL. breathing of the OL. It is apparent in fig (1) that the References: basic frequency or fundamental frequency (FF) of 1. I Bloch, 2005, Nature physics , 1, 23. oscillation in presence of only harmonic trap is 2. A Nath and U Roy, 2014, Laser Phys. Lett., 11, 115501. 3. I Bloch, 2004, Phys. World, 17, 25. present with highest amplitude. Additionally, some 4. A Nath and U Roy, 2014, J. Phys. A: Math. Theor, 47, higher and lower frequencies are also visible at 415301. regular intervals from FF. This is depicted in fig (2). 5. I Vidonović et al., 2011, Physical Review A, 84, 01361. Subsequently, these side band frequencies (SBF) are 6. V M Pe´rez-Garcı´a et al., 1997, Physcial Review A, 56(2), 1050. also correlated to the FF. 7. A M Kamchatnov et al.,2004, Physical Review A, 70, a)[email protected], b)[email protected] 02360 117 ISAMP TC-7, 6 8 January, 2018, Tirupati CC006D Udaykumar − A pedagogical simulation of the Aharonov-Bohm effect Voma Uday Kumar and P C Deshmukh Indian Institute of Technology Tirupati, Tirupati – 517506 Topic: Ion traps, Laser cooling (D, C) In the Aharonov-Bohm experiment, it was seen that the quantum phase of an electron could be altered to detectable extent by a magnetic field even in a region where the field intensity is zero [1,2]. Dramatic effects of the AB effect for trapped ions were reported decades ago [3]. In a recent paper, Nogochi et al. reported [4] that charged particles in quantum tunneling system are coupled to the magnetic vector potential even during quantum tunneling, in accordance with the Aharonov–Bohm effect. The results of Noguchi et al. paper [4] on the tunneling of a quantum rotor in a Paul trap has created much interest in the study of the ABE and Berry Phase [5] among scientists working in the Fig.1: The dashed line shows the envelope of the area of ion-trap studies, laser cooling, BEC etc. interference pattern with no current in the solenoid, This topic is of great interest even in the and the continuous line enclosing the shaded portions understanding of the gravitational field as it is shows the same when the current is switched on. possible that particles are affected by the gravitational potential even in the absence of a We trust that the simulation developed will be of force. Ultracold atoms have been employed to interest to both theorists and experimentalists demonstrate this remarkable phenomenon [6]. In working in the field of ion traps. the present work, we report a computer simulation of the AB effect toward a pedagogical References: discussion on the exciting quantum [1]Aharonov,Y.,& Bohm,D et al.(1959).Significance phenomenology. of Electromagnetic Potentials in the Quantum theory. Physical Review, 115(3), 485–491. The MATLAB GUI Software has been employed [2]M. V. Berry, F.R.S. et al.(1984). Quantal phase to elucidate the AB effect from a fundamental factors accompanying adiabatic changes. Proc. R. Soc. point of view. In the figure shown below we show Lond. A 392, 45-57. [3]Robert R.Lewis et al.(1983).Aharonov-Bohm the results of the simulation in which the effect for trapped ions. Physical Review A volume 28 interference pattern in a Young’s double slit [4]Atsushi Noguchi et al.(2014). Aharonov–Bohm experiment with electrons is phase shifted by the effect in the tunneling of a quantum rotor in a linear magnetic vector potential created by a long Paul trap. solenoid despite the fact that the elecrtons do not NatureCommunications,DOI: 10.1038/ncomms4868. at any point enter the region of the solenoid’s [5]Michael A. Hohensee et al.(2012).Force-Free magnetic field. Gravitational Redshift: Proposed Gravitational Aharonov-Bohm Experiment. Phys. Rev. Lett. 108, 230404. [6]Matt Jaffe1 et al (2017).Testing sub-gravitational forces on atoms from a miniature in-vacuum source mass. DOI: 10.1038/NPH 118 ISAMP TC-7, 6 8 January, 2018, Tirupati CD001 Dutta − Cooling of trapped ions with a tiny cloud of ultracold atoms: the role of resonant charge exchange Sourav Dutta1 and S. A. Rangwala Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore – 560080, India. Topic: D - Trapping and manipulation of quantum systems. Trapping and cooling of ions have been in- the ion. The result raises hope that cooling of + + + 6 strumental in advancing numerous fields includ- H2 , H3 and HD with ultracold Li atoms may ing precision measurements, quantum compu- now be possible. ting, quantum simulations and cold chemistry. In the second part of the presentation, I shall Demonstration of new ion cooling methods is discuss our experiments which demonstrate, for therefore of paramount importance in the ad- the first time, a novel ion cooling mechanism vancement and expansion of these research are- based on inelastic, resonant charge exchange as. Optically dark ions such as Na+, Rb+, Cs+ collisions between the trapped ion and the par- cannot be laser cooled, leaving cooling by colli- ent neutral atom [2]. Specifically, we experi- sions with cold atoms as the next most viable mentally demonstrate cooling of trapped 133Cs+ option. Indeed, experiments have time and ions by collisions with co-trapped, ultracold again verified that an ion trapped in a Paul trap 133Cs atoms and, separately, by collisions with can be cooled by elastic collisions with cold at- co-trapped, ultracold 85Rb atoms. We observe oms when the ion is heavier than the atom. that the cooling of 133Cs+ ions by 133Cs atoms is However, there is a long-standing debate on more efficient than cooling of 133Cs+ ions by whether the reverse, cooling of low-mass ions 85Rb atoms. This indicates the presence of a by higher-mass atoms, is possible. cooling mechanism beyond elastic ion-atom In the first part of my presentation, I shall collisions for the Cs-Cs+ case, which is cooling discuss our experiments which demonstrate, for by resonant charge exchange. The efficiency, the first time, cooling of low-mass ions by ul- per-collision, of cooling by resonant charge ex- tracold heavier atoms [1]. Specifically, we show change is established to be higher than cooling that 39K+ ions trapped in a Paul trap are cooled by elastic collisions. The results provide an ex- by ultracold 85Rb atoms trapped in a magneto- perimental basis for future studies on charge optical trap (MOT), provided the MOT is cen- transport by electron hopping in ultracold atom- tered with the Paul trap. A similar cooling of ion systems [3]. 85Rb+ ions by ultracold 133Cs atoms is also demonstrated. The ions are cooled because the References ultracold atoms are localized and placed pre- [1] Dutta S, Sawant R, Rangwala S A. 2017 Physical cisely at the centre of the ion trap, where the Review Letters 118 113401 ion’s secular speed is the maximum. Therefore, [2] Dutta S, Rangwala S A. 2017 arXiv:1705.07572 elastic collisions with ultracold atoms always [3] Côté R. 2000 Physical Review Letters 85 5316 reduce the speed, and hence the temperature, of 1E-mail: [email protected] 119 ISAMP TC-7, 6 8 January, 2018, Tirupati CD002 Bayen − Quantum dynamics and frequency shift of a Driven multi-photon anharmonic oscillator Dolan Krishna Bayen * 1 and Swapan Mandal * 2 * Department of Physics, Visva-Bharati, Santiniketan-731235, INDIA Topic: D The Hamiltonian and hence the relevant fundamental nature of the problem, the equations of motion involving the dynamics of problems of anharmonic oscillator have a driven classical anharmonic oscillator with attracted people from various branches of 2m − th anaharmonicity are framed. By physics [1-9].The solution of driven anharmonic neglecting the nonsychronous energy terms, we oscillator is explored under the RWA and is derive the model of a driven multi-photon certainly based on the complete analytical (2m − th) quantum anharmonic oscillator. The approach. The present solution will find dynamical nature of the field operators are applications in the investigation of quantum expressed in terms of the coupling constant, statistical properties of the radiation fields and excitation number and the driven parameter. in the dynamics of the trapped particles in a The solutions presented here are fully analytical MOT. These quantum statistical properties and are exact in nature. The basic physics is include squeezing, higher ordered squeezing, easily understood in terms of models. Of photon antibunching and photon statistics. course, the model of a harmonic oscillator (HO) is perhaps the most useful one among them. The References model of a simple harmonic oscillator is [1] A H Nayfeh, Introduction to perturbation realized when a particle moves under the action techniques (Wiley, New york, 1981). of restoring force. In spite of the wide applications of the SHO model, it is inadequate [2] A H Nayfeh and D T Mook, Non-linear when we come across with the real physical oscillations (John Wiley, New york, 1979). situations. For a real physical system, the inclusion of damping and/or anharmonicities [3] R Bellman, Methods of nonlinear analysis Vol.1 are inevitable. In addition to these, the oscillator (Academic press, New york, 1970) p.198. may also be put under the action of an external [4] S L Ross, Differential equation 3rd eds. (John Wiley, force and hence the model of a forced (driven) New york, 1984). oscillator. It is true that the presence of damping in the model of a SHO is not a serious problem [5] S Mandal, Physics Letters A, 299, 531, (2002). as long we are interested in the classical regime. On the otherhand, the presence of damping in [6] S Mandal, J.Phys.A 31, L501 (1998). the model of a SHO makes the problem a nontrivial one. Therefore, the damped quantum [7] C C Gerry, Physics Letters A, 124, 237, (1989). harmonic oscillator requires a special attention. In this communication, we will ignore the [8] V Buzek, Physics Letters A, 136, 188, (1989). presence of damping if any. Because of the [9] R Tanas, Physics Letters A, 141, 217, (1989). wide range of applications and of the 1 E-mail: [email protected] 2 E-mail: [email protected] 120 ISAMP TC-7, 6 8 January, 2018, Tirupati CD003 KumarSugham − High-intensity laser ion experiments in Penning Trap 1 , , , Sugam Kumar ∗ , S.Ringleb †, N.Stallkamp † ‡, M.Vogel ‡, W.Quint ¶, Th. Stohlker † ‡ §, , G.G.Paulus † §, C.P Safvan ∗ ∗ Inter University Accelerator Centre, New Delhi – 110067, Delhi, India † Institute of Optics and Quantum Electronics, Friedrich-Schiller-Universitat – 07743, Jena, Germany ‡ GSI Helmholtzzentrum for Schwerionenforschung GmbH – 64291, Darmstadt, Germany § Helmholtz-Institut Jena – 07743, Jena, Germany ¶ Physikalisches Institut, Ruprecht Karls-Universitat Heidelberg – 69120, Heidelberg, Germany Topic: D We have designed and constructed a mechan- tube to decelerate ions for dynamic capture of ically compensated Penning trap to study the externally produced ions, for example from an behaviour of atomic and molecular systems in EBIT or a beamline. extreme electromagnetic fields. This is realized For non-destructive ion detection we use res- by the preparation and confinement of atomic onant amplification of mirror currents induced in and molecular ion targets in a Penning trap, and the trap electrodes by the ion oscillations. Two the non-destructive analysis of reaction prod- high quality factor resonators with resonant fre- ucts upon interaction with high-intensity laser quencies of 229kHz and 702kHz are employed to light. For a determination of absolute reaction measure the axial frequencies whereas a helical cross sections, it is crucial to identify and count resonator which amplifies multiples of fundamen- both the educts and products. Therefore, we tal frequencies is the used to measure cyclotron have designed and built the HILITE (High Inten- fre-quencies. By tuning the trap potential, this sity Laser Ion-Trap Experiment), which employs allows to measure charge-to-mass ratio spectra of several Penning-trap techniques for ion capture, the confined ions over a broad range. To be also confinement, selection and ion-target formation. sensitive to a small ion numbers, we apply a de- To cover a broad range of laser parameters it is structive measurement technique. Using a MCP necessary to have access to different laser sources. detector-system with a timing anode we are able The setup is hence built in a compact fashion to measure even single ions, when ejecting the which allows it to be moved easily from one lo- reaction products out of the trap. cation to the other. The main focus concerning measurement performance lies on versatility and reliability. The trap electronics is located in the bore of a 6T superconducting magnet. The trap itself located in the centre of the magnetic field, where Figure 1. Schematic of Trap electrodes and Baffles the homogeneity magnetic flux density is better than 10ppm. The trap is a cylindrical open- endcap design with access from both sides for The plan includes the use of the PHELIX in-coupling of the laser beam and ion injection laser with wavelength 1053 nm at GSI and from an external source. In order to achieve long POLARIS (1030 nm) and JETI (800 nm) at ion storage times the design residual gas pres- Jena, Germany with intensities up to order 12 21 2 sure is better than 10− mbar. To compromise 10 W/cm . We present the current status of this open design with a sufficient vacuum in the the experiment and the results of the character- interaction region, a set of baffles at cryogenic ization experiments of our ion trap. temperatures is applied on each side of the trap- electrodes. Furthermore we use one set of baffles References as a single-pass charge counter to characterize the ion bunches entering and leaving the trap. [1] Gabrielse et al. 1989 IJMSIP 88 319 Another set of baffles is used as a pulsed drift [2] M. Richter et al. 2009 PRL 102 163002 1E-mail: [email protected] 121 ISAMP TC-7, 6 8 January, 2018, Tirupati CD004 Prakash − Non-linear Axial Oscillations of an Electron plasma in a Penning Trap 1 2 3 4 Prakash∗ , Durgesh Datar∗ , Dyavappa B M∗ , Sharath Ananthamurthy† ∗ Department of Physics, Bangalore University, Bengaluru – 560056, Karnataka, India † School of Physics, University of Hyderabad, Hyderabad – 500046, Telangana, India Topic: D We have obtained experimentally the mo- bling behavior as the excitation field strength is tional resonance spectrum of an electron plasma increased, is being examined currently. confined in a Penning trap. This is obtained through weak dipole excitation of the centre of A) B= 309 G, Power= -20dBm, Pressure= 2*10-8 I = 1.4 A, V = -0.8 V, Voltage= 10 V fil bias mass eigen frequencies of particle collective mo- 2.0 tion as well as the frequencies due to coupling of the degrees of freedom. Even under low excita- 1.9 1.8 3ω 4ω tion strengths of the radio frequency source the − z axial oscillation resonance exhibits, apart from 1.7 individual and collective particle oscillations of Signal Height(a.u.) 1.6 2ω the electron plasma, higher order resonances as z well. Both particle oscillation components have 1.5 ω ω z ω c different shape and width. The behavior of the 1.4 � center-of-mass resonance suggests that it is a 0 200 400 600 800 Frequency (MHz) parametric instability of a Mathieu type equa- B= 309 G, Power= -10dBm, Pressure= 2*10-8 B) I = 1.5 A, Voltage= 10 V tion of motion[1]. fil 2.0 In this experiment, the axial electron plasma 1.8 �ω 3ω z oscillations are excited by sweeping the frequency 1.6 z 4ω z of an applied rf-field by using an external an- 1.4 ω ω tenna. A number of resonances are visible which 1.2 − z appear not only at the fundamental frequencies 1.0 �ω z 0.8 ω+, ω and ωz but also at linear combinations Signal Height (a.u.) − 0.6 of these frequencies. Here ωc, ω+, ω and ωz are − 0.4 respectively the free electrons cyclotron, the per- ω � ω turbed cyclotron, the magnetron and axial fre- 0.2 c 0 200 400 600 800 quencies of oscillation. Frequency (MHz) In previous work[1,2] the axial oscillation at Figure 1. Motional resonance spectrum of an elec- 2ωz is examined under higher resolution. This tron cloud obtained for magnetic field 309 Gauss reveals the structure of a broad asymmetric min- and RF power is (A)-20dBm, (B) -10dBm for stor- imum in the electron number, accompanied by a age voltage 10 Volts. sharp resonance on the high frequency side. The asymmetry in the low-frequency component is as- cribed to non-linearity in the trapping potential. References In our measurements we have observed the axial resonances of order higher than 3ωz. These [1] Paasche. P et al. 2002 The European Physi- higher order axial resonances have not been ob- cal Journal D-Atomic, Molecular, Optical and served so far, for any traps geometries. The be- Plasma Physics 18 295-300 havior is modeled by including a cubic nonlinear- [2] Tommaseo. G et al. 2004 The European Phys- ity term in the equation for the oscillating elec- ical Journal D-Atomic, Molecular, Optical and tron plasma in the trap. Possible period dou- Plasma Physics. 28 39–48 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 4E-mail: [email protected] 122 ISAMP TC-7, 6 8 January, 2018, Tirupati CD005 Gangwar − A Novel Cooling Process Using Autoresonance in an Electrostatic Ion Beam Trap R. K. Gangwar,1,* K. Saha,1 O. Heber,1,# M. L. Rappaport,2 and D. Zajfman1 1Department of particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot, Israel 7610001 2Physics Core Facilities, Weizmann Institute of Science, Rehovot 7610001 Israel *Email: [email protected],[email protected] Topic: D Trapping and manipulation of quantum systems Control of kinematic as well as internal degrees of freedom of ions is a basic requisite in many branches of physics, such as spectroscopy, funda- mental quantum physics, quantum electrodynamics and quantum computation. It enables detailed ex- periments such as studies with merged beams where precise control of kinetic energies of the two beams permits fine-tuning of their relative velocities. Therefore many techniques to control the external and internal degrees of freedom of molecular ions have been proposed and implemented in various traps. Recently, we demonstrate a simpler approach that can easily be implemented in any electrostatic storage device, i.e., a technique applicable to all trapped ions irrespective of their charge and mass. We have successfully reduced a relatively wide ini- tial longitudinal momentum distribution (Δp/p) of a bunch of ions oscillating inside an electrostatic ion beam trap (EIBT) by at least an order of magnitude to temperatures well below 1 K. This reduction was achieved by applying adiabatic autoresonance (AR) acceleration, which removes from the bunch the ions that are at the edges of the momentum distribu- tion, Δp, so that the distribution in the bunch nar- rows, albeit with fewer particles. At the same time, ion-ion interaction near the turning points in the mirrors enhances thermalization within the bunch. This scheme is similar to evaporative cooling that removes particles at the high end of the momentum distribution. We have extended these techniques to explore whether ion-ion interactions can lead to control the ro-vibrational degrees of freedom of molecular ions. Our preliminary results are encouraging and further experiments are currently being conducted. Detailed results and explanation of the technique shall be presented. References [1] R. K. Gangwar, et al, Autoresonance cooling of ions inside an electrostatic ion beam trap, Phys. Rev. Lett., 119, 103202 (2017). *Email: [email protected] # E-mail: [email protected] 123 ISAMP TC-7, 6 8 January, 2018, Tirupati CE001 Chacko − Development of a 22-pole radio-frequency ion-trap experimental set-up to study ion-atom and ion-photon collisions of astrophysical interests 1 ,#2 3 Roby Chacko∗ , P. C. Deshmukh† , & G. Aravind∗ ∗ Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India † Department of Physics, Indian Institute of Technology Tirupati, Tirupati, 517506, India # Department of Physics, Indian Institute of Science Education and Research, Tirupati, 517507, India Topic: E. Development of major experimental facilities for AMO Physics and Laboratory Astrophysics We are developing a major experimental facil- trometer (QMS) for parent ions, 22-pole ion-trap, ity to trap ions using a 22-pole radio-frequency QMS for daughter ions and a detector. The ion-trap [1,2] at IIT Madras, with an aim to trapped ions could also be cooled via buffer gas do laboratory astrophysics experiments. We are cooling for effective trapping and for studying mainly interested in studying ion-atom collision collisions at low temperatures. reactions and ion-photon collision reactions in The ion-trap is made out of OFHC copper inter-stellar medium(ISM) conditions, by simu- with Molybdenum rods as electrodes, with ut- lating the ISM conditions in the laboratory. The most precision. We had developed our own radio- setup can also be employed to address a vari- frequency power source, a synchronized control- ety of problems in fundamental physics and in- ling and data acquisition cum analysis system terdisciplinary areas ranging from ion-atom colli- for the QMS-detector combined system, a liq- sions at low temperatures to the photoabsorption uid nitrogen based coldhead which can cool the by biomolecules such as the retinal chromophore, trapped ions as low as 80K and quadrupole ion- which is responsible for our colour vision. benders for bending the ions by 900. We will be presenting our initial results of trapping the ions in the conference. Ion-atom collisions will be per- formed within the trap. We aim to study the for- mation of large ISM dusts beginning from small poly aromatic hydrocarbon (PAH) anions. The formation of complex large PAHs and the stabil- ity of PAHs against collisions with photons and matter under low temperature conditions is im- portant to understand the ISM dynamics [3,4]. The set-up will be employed to do temperature dependent reaction rate studies, which would re- veal the reaction dynamics at various regions of ISM with temperature gradients. References [1] Gerlich D., 1995 Phys. Scr. T59, 256-263 Figure 1. Schematic of the experimental set-up [2] Wester R., 2009 J. Phys. B: At. Mol. Opt. Phys. 42, 154001 As depicted in the schematic diagram, the [3] Gerlich D., Smith M., 2006 Phys. Scr. 73, C25 complete setup consists of a pulsed supersonic [4] Smith I. W. M., Rowe B. R., 2000 Acc. Chem. res expansion anion source, Quadrupole Mass spec- 33(5), 261-268 1E-mail: [email protected] 2E-mail: [email protected] 3E-mail: [email protected] 124 ISAMP TC-7, 6 8 January, 2018, Tirupati CE002 Sharma − Towards a search for Dark Matter candidates using atomic Dysprosium Arijit Sharma* 1, Mahapan Leyser*, Anna V. Viatkina*, Lykourgos Bougas*, Dmitry Budker*† 2 * Helmholtz-Institut Mainz (HIM), Johannes Gutenberg Universität, Mainz 55128, Germany † Institut für Physik, Johannes Gutenberg Universität, Mainz 55128, Germany Topic: E. Studies of rotation curves of galaxies, initiated by by 15 orders of magnitude), and most recently, a Oort & Zwicky (1930`s) and later by Rubin search for possible exotic interactions sourced by (1970`s) led to the Dark Matter (DM) hypothesis massive bodies and mediated by light scalar bosons and the subsequent evidence for the existence of [5]. Dark Matter and Dark Energy. Search for the elu- sive dark matter candidates has been going on since We are proposing to use the same system for per- the early 1970`s. Oddly the Standard Model (SM) forming precision ISS (Isotope Shifts Spectroscopy) with all its tremendous successes (most notably, in measurements with sub-Hz precision, with the aim the recent past, being the discovery of the Higgs of searching for New Physics (NP) beyond the boson at the LHC, CERN) has so far failed to pro- Standard Model (BSM) through possible non- vide an insight into the candidates that may directly linearities that may arise on a King Plot (KP). The or indirectly relate to Dark Matter or Dark Energy. idea is based on isotope shifts spectroscopy (ISS) and establishing a King Plot (KP) through frequen- Experimental efforts have also been initiated for cy measurements across multiple isotopes searches of axions and WIMPs (Weakly Interacting of dysprosium (Dy) in the RF (Radio Frequency) Massive Particles), who are potential Dark Matter and the optical domain. In an ideal scenario, the candidates, with the recent results on WIMPS pub- King Plot (KP) is linear with mass and frequency lished from the XENON1T [1] and PANDAX-II ratio scaling measured for two different transitions [2]. However, these experimental searches includ- across multiple isotopes. Non-linearities in the King ing the ones at the LHC, CERN have still not pro- Plot may arise from possible dark matter candidates duced any definitive outcome related to the origin that couple to the atomic nucleus and electrons and still yet elusive, Dark Matter particles. In our through short range forces. I shall present our ex- group, we are trying to search for possible Dark perimental efforts that have been initiated towards Matter (DM) candidates through precision atomic this end with an emphasis on the current status and spectroscopy on dysprosium (Dy) atoms. possible experimental outcomes. Dysprosium (Dy) is an atomic system that has in References the past been used for searching for possible varia- [1] E Aprile et al. 2017 Phys. Rev. Lett., 119, 181301 tions of fundamental constants [3] with the aim [2] Xiangyi Cui et al. 2017 Phys. Rev. Lett., 119, of constraining possible dark matter candidates 181302 and also exploited for the search of parity-violating [3] N. Leefer et al. 2013 Phys. Rev. Lett. 111, effects mediated by cosmic fields that may be part 060801 of dark matter. This experiment was also used to- [4] K. van Tilburg et al. 2015 Phys. Rev. Lett. 115, wards a search for ultralight dilatonic dark matter 011802 [4] (that was also used to improve constraints on [5] N. Leefer et al. 2016 Phys. Rev. Lett. 117, possible quadratic interactions of scalar dark matter 271601 1 E-mail: [email protected] 2 E-mail: [email protected] 125 ISAMP TC-7, 6 8 January, 2018, Tirupati CF001 Momeen − Development of nanoscale magnetometry using nitrogen-vacancy center in diamond M. Ummal Momeen*1, and Jianping Hu†2 * Department of Physics, School of Advanced Sciences, VIT University, Vellore-632014, Tamil Nadu, India †Department of Chemistry, School of Advanced Sciences, VIT University, Vellore-632014, Tamil Nadu, India Topic: F Measurement of weak magnetic fields with tems because it can be spin polarized by opti- high precision and spatial resolution is an in- cal excitation even at room temperature, and teresting challenge for scientists. Among the the spin state of a single NV can be read out solid state devices, the most sensitive magnetic optically. In addition to the high sensitivity and sensors are based on Superconducting Quan- nanoscale spatial resolution, the large dynamic tum-Interference Devices (SQUID) [1]. How- range is also a challenging requirement for an ever, these devices are in need of cryogenic excellent magnetic field measurement/imaging cooling and do not have the intrinsic absolute techniques. In this work we focus on the de- calibration of the field. Atomic vapor cell sign and construction of experimental setup for magnetometers [2] can be used for high sensi- nitrogen-vacancy center in diamond research, tivity measurements at room temperature. An which will be a platform for pursuing the re- atomic magnetometer can have excellent sen- search in the direction of nanoscale spatial sitivity but it has only the millimeter range spa- resolution magnetometry for magnetic samples tial resolution. A magnetic resonance force mi- and also for the study of quantum information croscopy (MRFM) [3] can perform with both science. The schematic of our proposed expe- high sensitivity and high spatial resolution for rimental arrangement is depicted in Figure 1. imaging any magnetic samples, but it needs cryogenic environment and in many cases the magnetic field of the magnetic tip (the detector of the MRFM) alters the magnetic characteris- tics of the sample to be measured. The finest magnetic field sensor should combine high sensitivity, nanoscale spatial resolution and wide operating temperature range (from am- bient room temperature to harsh cryogenic conditions). The study of nitrogen-vacancy (NV) center in diamond has gained lot of attention in recent years [4] because it has applications in nanoscale single spin magnetometry, nanoscale thermometry in a living cell and quantum in- formation processing. The NV center is a solid Figure 1. Schematic diagram of NV center state defect in diamond, where a substitutional magnetometry setup. nitrogen impurity atom lies adjacent to a va- References cancy in the diamond lattice. It has been dem- onstrated that the NV center in diamond is a [1] J. P. Cleuziou et al. 2006 Nat. Nano 1 53 suitable candidate for probing weak magnetic [2] H. B. Dang et al. 2010 Appl. Phys. Lett 97 fields with high sensitivity and nanoscale spa- 151110 tial resolution even under ambient conditions. [3] H. J. Mamin et al. 2007 Nat.Nano 2 301 NV center is unique among the solid state sys- [4] M. S. Grinolds et al. 2013 Nat.Phys 9 215 1 E-mail: [email protected]; 2 126 E-mail: [email protected] ISAMP TC-7, 6 8 January, 2018, Tirupati CF002 Hu − Novel tunable near field broadband microwave antenna designs for nitrogen-vacancy center in diamond Jianping Hu†1, and M Ummal Momeen*2 † Department of Chemistry, School of Advanced Sciences, VIT University, Vellore – 632014, Tamil Nadu, India * Department of Physics, School of Advanced Sciences, VIT University, Vellore – 632014, Tamil Nadu, India Topic: F Nitrogen-vacancy center (NV center) is an this PCB based antenna. The copper trace con- atomic defect in diamond. As a precision quan- tacting the diamond plate is masked with solder tum sensor, it has broad applications in quantum resist to avoid fluorescence from copper. The information and quantum computation networks input impedance of this antenna is 50 Ω. [1]. The electronic spin in a NV center can be manipulated by microwave and addressed using optical transitions [2]. To deliver microwave to the NV centers, thin copper wire, loop coil, double split-ring resonator and planar ring resonator were devel- oped [3-6]. However detailed considerations to all the aspects including microwave power effi- ciency, spatial homogeneity of microwave magnetic field, wide bandwidth, access to opti- cal path, simultaneous control mechanisms were not present together in these existing designs. We demonstrate a novel microwave near field antenna specifically designed for manipu- lation of NV centers in diamond. It is tunable and the precise fabrication requirement is ab- ated. The working frequency is centered around 2.87 GHz with broad bandwidth. It ensures the detection of high dynamic range external mag- netic fields and waivers the need of tuning and matching of the antenna. It also imparts spatial homogeneity of microwave magnetic field with- in the diamond with the range of millimeter, Figure 1. Novel tunable near field broadband mi- crowave antenna for NV center diamond. easing wide spatial range magnetic-field imag- ing. It is power efficient and the power rating References requirement of microwave power amplifier is ambient. These advantages facilitate the expe- [1] L. Childress et al. 2013 MRS Bull 38 134 riments on high dynamic range magnetic field [2] F. Jelezko et al. 2006 Phys. Stat. Sol. (a) 203 sensing and imaging via NV centers. 3207 Figure 1(a) shows the structure of this near [3] L. Childress et al. 2006 Science 314 5797 [4] M. Chipaux et al. 2015 Eur. Phys. J. D 69 166 field microwave antenna etched from PCB. The [5] K. Bayat et al. 2014 Nano Lett. 14 1208 setup to deliver microwave to the diamond plate [6] K. Sasaki et al. 2016 Rev. Sci. Instrum. 87 with NV centers is shown in Figure 1(b). Figure 053904 1(c) illustrates the cross sectional structure of 1 E-mail: [email protected]; 2 E-mail: [email protected] 127 e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018 Tirupati and the Host Institutes e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018 About Tirupati Tirupati, located within the hills of Eastern Ghats, is a heritage city of tremendous religious importance. The place is considered one of the holiest Hindu pilgrimage sites because of Tirumala Sri Venkateswara Temple, which is located on the seventh peak of Tirumala Hill. It is one amongst the eight most holy and worshipped places of Lord Mahavishnu. Sri Govindarajaswami Temple is also very important shrine in Tirupati. Another famous destination sought by pilgrims is Srikalahasti, situated on the banks of Swarnamukhi River. Sri Venkateswara Temple Apart from being scattered with ancient temples and shrines, the nearby areas are famous for their beauty and serenity. Adjacent to the Sri Venkateswara Temple are the massive 460 acre TTD Gardens having an impressive range of flowers. Flowers from this garden are supplied to the religious places in and around Tirumala. Surrounded by the Seshachalam Hills of the Eastern Ghats, the area is rich in flora and fauna. The hills also host the highest waterfall ‘Talakona waterfall’ in the state, which is situated at about 50 km from Tirupati and is regarded as the main entrance to the Tirumala Hills. There are several natural creations like the Silathoranam (rock garland), a natural arch, very close to Sri Venkateswra temple in Tirumala hills. The arch measures 8 m in width and 3 m in height. For wildlife lovers, Sri Venkateswara national Park is definitely the place to visit. Sri Venkateswara zoological park, museum, regional science center are other major tourist attraction in Tirupati. Talakona Waterfall Tirupati is also one among hundred Indian cities to be developed as a smart city under Smart Cities Mission by Government of India. Tirupati is also home to many educational institutions and universities. Apart from IISER, the place hosts IIT, Sri Venkateswara University and many engineering colleges as well. Along with the religious and scenic reasons, shopping experience in Tirupati is also something that you would want to indulge in. The place is famous for unique handicrafts such as woodcarvings and traditional Tanjore Natural Arch style Gold Leaf paintings, famous for their mythological motifs and themes. The place also offers a flattering number of choices for food with Tamil, Andhra and Hyderabadi cuisines. Telugu is the official and widely spoken language. Tamil, Kannada and Hindi are the other languages spoken due to the large number of visiting pilgrims. Tirupati deals with extreme summers, however during monsoon season and winters, pleasant weather makes the ambiance pristine. b e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018 To reach Tirupati, frequent flights are accessible from major cities. Tirupati airport is nestled in the region of Renigunta and the adjacent International airport is Chennai from which the place has a good connectivity with different corners of the country and abroad. The main railhead of the place is Tirupati Railway Station that is linked with major cities. About IISER Tirupati The strategic plan to set up Indian Institutes of Science Education and Research was the outcome of a recommendation of the Scientific Advisory Committee to the Prime Minister of India. It suggested the establishment of Institutes for teaching basic sciences with state of the art research facilities, which would motivate faculties to attract meritorious students to have their careers in basic sciences. Five IISERs were established under the umbrella of MHRD during the period 2006-08 at Kolkata, Pune, Mohali, Bhopal and Thiruvananthapuram. Today, the IISERs have established themselves as leadership institutions for basic sciences and declared by the Act of Parliament as the institutions of national importance, nurturing advanced education and frontier research. IISER Tirupati is the sixth Institute under the chain of IISERs, established by the Govt. of India under the ministry of HRD as an Institute of National Importance. The foundation stone for the Institute was laid by the then HRD Minister, Smt. Smriti Zubin Irani, on March 28, 2015 at the 250 acre land in Yerpedu village on Tirupati -Venkatagiri highway, earmarked for the establishment of the permanent campus. The campus currently operates from a transit site at Sree Rama Engineering College. IISER Pune was designated as the mentor institute and its Director, Prof. K N Ganesh was appointed as the mentor Director for IISER Tirupati (who is currently the Founder Director of the institute). The academic program of the institute started in August, 2015 with the admission of 50 students as the first batch of its BS-MS program. The PhD program at IISER Tirupati was initiated in August 2017. Currently the institute has over 250 BS-MS and PhD students. In addition to imparting rigorous undergraduate education, the faculty at the institute pursue state-of-the-art research in several contemporary areas including Neuroscience, Plant biology, Ecology and evolution, Cancer biology & Immunology, Infectious disease, Organic & Biochemistry, Inorganic & Materials Chemistry, Theoretical, Analytical & Physical Chemistry, Earth and Climate Sciences, Microfluidics, Astronomy & Astrophysics, Condensed Matter Theory, Particle Physics, Atomic and Molecular Physics, String Theory, Topology, Harmonic Analysis, Number Theory, Differential Geometry, and Non-Linear Dynamics among other interdisciplinary areas. IISER Tirupati transit campus c e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018 About IIT Tirupati The Indian Institutes of Technology (IITs) are highly prestigious autonomous public institutions for higher education and research in technology and basic sciences in India. They are governed by the Institutes of Technology Act, 1961, Government of India, which declares them as the Institutes of National Importance. IIT Tirupati was started in March, 2015 along with five other 3rd generation IITs at Palakkad, Jammu, Bhilai, Goa, and Dharwad increasing the count of IITs to 23 spread across the country. Presently, it is operating from a temporary campus on the Tirupati–Renigunta road, and plans are well under way to set up its own campus in the next 3 or 4 years at a site (about 530 acres in extent) at Merlapaka Village, Yerpedu Mandal, Chittoor District, Andhra Pradesh (14 km from the Tirupati airport). The transit campus is fast coming up at the permanent campus site and would be operational by the next academic year (2018). The Institute started functioning with the support of its mentoring Institute, IIT Madras, from the academic year 2015–16 and growing very rapidly under the leadership of Prof K. N. Satyanarayana, the founder director. The academic programme was launched in August 2015 with 120 students to the B. Tech programme in four disciplines of Engineering. The MS (Research) and PhD programs for January 2018 semester were initiated. At present, the institute has approximately 400 students in various undergraduates and post graduates disciplines and more than 40 regular faculty members. IIT Tirupati is expected to be a 12,000-student campus in the coming decades. It is expected that within a few years the Institute would be able to put in place excellent infrastructures required to house a strong student community and corresponding world class faculty, state-of-the-art laboratories etc. Apart from the teaching activities, IIT Tirupati has been enthusiastically involved in frontline research in both basic science and technology. Some of the thrust research areas of the institute are smart infra-structure, education technology, energy and environment, materials and nano science. IIT Tirupati transit campus d e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018 Map of Tirupati with important contacts e e-Conspectus: ISAMP-TC7, Tirupati, 6—8 January 2018 Map of Tirupati II f