The University of Hull a Matrix Isolation Study of Transition Metal

Total Page:16

File Type:pdf, Size:1020Kb

The University of Hull a Matrix Isolation Study of Transition Metal The University of Hull A Matrix Isolation Study of Transition Metal Halides and their Structure. being a Thesis submitted for the Degree of Doctor of Philosophy in the University of Hull by Antony Wilson, B.Sc. June 09 i This thesis is the result of my own work, except where due reference is given. No part of this work has been, or is currently being, submitted for a degree, diploma or other qualification at this or any other university or higher education establishment. This thesis does not exceed the 100,000 word limit, including tables, footnoted, bibliography and appendices. Antony Wilson ii Abstract The work within this thesis has concentrated on the formation and isolation of titanium, vanadium, palladium, and mercury halides, with emphasis on the fluorides. TiF, TiF2, TiF3, and TiF4 have all been isolated within an argon matrix and infrared spectra obtained. From the titanium isotope splitting pattern a bond angle has been determined for o TiF2 for the first time of 165 , or effectively linear. This work is also the first time that TiF has been isolated within an argon matrix. Work has also been conducted with vanadium which has lead to the isolation of VF5, VF4, VF3, and VF2, with VF4 undergoing Fermi Resonance. This is the first time that VF4 and VF2, consistent with a linear structure, have been isolated within a matrix. Work conducted upon palladium led to the isolation of numerous palladium fluorides, identified by the palladium isotope patterns in their IR spectra. Due to the similarity of the calculated stretching frequencies of PdF2, PdF3, PdF4, and PdF6 the assignment was challenging and so identification of these bands was conducted based photolysis and annealing behaviour in conjunction with computational calculations. This has allowed for the assignment of the bands present to PdF6, PdF4, PdF3, PdF2, and PdF. The bond length of molecular HgF2 has also been determined for the first time at 1.94(2) Å using the Hg L3-edge with EXAFS. Although the initial aim of this work was to isolate HgF4, using IR, UV/Vis, and XANES, no evidence could be found for oxidation states of II mercury higher that Hg . The work also developed a new clean way of making HgF2 in a matrix. The identification of a new Hg…X2 complex was also discovered which when photolysed forms the HgX2 compound, this has only been proven for HgF2. This was achieved by isolating mercury atoms in an argon matrix doped matrices, photolysis of this matrix the led to the formation of HgF2 in significant amounts. iii Acknowledgements. I would like to extend my deepest gratitude to my supervisor, Dr. Nigel Young, for offering me this opportunity and for his continued patience and guidance throughout the course of this work. I would also like to thank Dr. Adam Bridgeman for granting this studentship to me initially and his supervision in the initial year of my work, plus his computational contributions. Special thanks must go to project students over the years for their contributions to this work, and because I made a promise a mention also for Helen. I would also like to thank my parents for their unwavering support of my university studies and their continual emotional and financial support throughout my university life, without them this thesis would have never been produced and so this thesis is dedicated to them. I would like to thank the E.P.S.R.C. for a research studentship and to the University of Hull for funding, and all members of the Inorganic Chemistry department past and present for their input and support over the years. The mechanical workshop and the glass blowers must also get a thank you, without them this work would have stalled on many occasions. iv Contents Declaration ii Abstract iii Acknowledgements iv Chapter 1 Introduction 1.1 Introduction. 1 1.2 Matrix Isolation. 2 1.2.1 The History of Low Temperature Experiments. 2 1.2.2 Development of Matrix Isolation. 3 References. 4 Chapter 2 Matrix Isolation and Spectroscopic Techniques 2.1 Introduction. 6 2.2 Spectroscopic Methods. 8 2.3 Matrix Materials. 8 2.4 The Structure of the Matrix. 11 2.4.1 Close Packed Structure Under ‘Matrix Conditions’. 12 2.5 Matrix Effect. 13 2.5.1 Multiple Trapping Sites. 14 2.5.2 Molecular Rotation. 17 2.5.3 Matrix Shift. 18 2.5.4 Aggregation. 18 2.5.5 Coupling with Lattice Vibrations. 19 2.5.6 Phonon Bands. 19 2.6 Species Generation. 19 2.6.1 Direct Vaporisation. 20 v 2.6.2 Induction Heating and Pyrolysis. 20 2.5.3 Sputtering. 20 2.5.4 Electron Bombardment. 21 2.5.5 Laser Ablation. 21 References. 22 Chapter 3 Theory 3.1 Introduction. 24 3.2 Vibrational Theory. 26 3.2.1 Diatomic Molecules. 27 3.2.2 Polyatomic Molecules. 31 3.3 Group Theory. 32 3.4 Selection Rules. 40 3.5 SOTONVIB. 42 3.5.1 Wilson’s GF Method. 42 3.5.2 Determination of Bond Angles. 44 3.6 Electronic Spectroscopy (UV/Vis) 46 3.7 Effect of the Matrix on Spectroscopy. 48 3.8 Ultraviolet Photolysis of Precursor in the Matrix. 50 3.8.1 Results of Photolysis. 51 3.8.2 The Effects of Continued Photolysis. 53 3.9 X-Ray Absorption Spectroscopy. 54 3.9.1 EXAFS. 56 3.9.1.1 Data Analysis. 57 References. 59 Chapter 4 Experimental 4.1 Matrix Gases. 60 4.2 Mass Spectrometry. 62 vi 4.3 Fourier Transform Infrared (FTIR) Matrix Isolation Spectroscopy. 66 4.4 Matrix Isolation UV/Vis Spectroscopy. 72 4.5 Matrix Isolation EXAFS. 74 4.6 Experimental Considerations of Matrix Isolation. 77 4.7 Deposition Techniques. 79 4.7.1 Thermal Evaporation. 79 4.7.2 Furnace Evaporation. 80 4.7.3 RF Generator – Induction Heating. 82 4.8 Computational Calculations. 83 References. 84 Chapter 5 First Row Transition Metal Halides 5.1 Introduction. 86 5.1.1 History of Titanium and Vanadium. 87 5.1.1.1 Titanium. 87 5.1.1.1.1 Titanium Halides. 88 5.1.1.2 Vanadium. 89 5.1.1.2.1 Vanadium Halides. 90 5.2 Literature Review. 90 5.2.1 Theoretical/Calculations. 91 5.2.2 IR Data. 99 5.2.2.1 Titanium Fluorides in a Matrix. 100 5.2.3 ESR Studies on TiF3 and TiF2. 102 5.2.4 Conclusions from the Literature. 103 5.3 Experimental Results. 103 5.3.1 Introduction. 103 5.3.2 Titanium Results. 105 5.3.2.1 Ti in O2/Ar. 106 5.3.2.1.1 Ti in 10% O2/ Ar. 106 5.3.2.2 Ti in F2/Ar. 107 vii 5.3.2.2.1 Ti in 10% F2/Ar. 107 5.3.2.2.2 Ti in 0.63% F2/Ar. 108 5.3.2.2.3 Ti in 0.16% F2/Ar. 110 5.3.2.2.4 Ti in 0.3% and 0.2% F2/Ar. 112 5.3.2.2.5 Ti in 2% F2/Ar. 112 5.3.2.3 Ti in N2 and H2O in Ar. 113 5.3.2.4 Assignment of TiF4 and TiF3. 114 5.3.2.4.1 TiF4 in Ar. 114 5.3.2.4.2 TiF3 in Ar. 115 5.3.2.4.3 Mass Spectrometry Work with TiF3. 116 5.3.2.5 UV/Vis Spectroscopy. 116 5.3.2.6 Computational Work. 117 5.3.2.7 Discussion. 122 5.3.3 Vanadium Fluorides in a Matrix. 123 5.3.4 Conclusion from Literature. 125 5.3.5 Vanadium Isolated in F2/Ar 125 5.3.5.1 V in Ar. 127 5.3.5.2 V in 10%, 1%, 0.18% and 0.055% F2/Ar. 128 5.3.5.3 New Methods of Vanadium Evaporation. 132 5.3.5.3.1 V in a F2 and Ar ‘Sandwich’ Method. 132 5.2.5.3.2 V with Protective Ar and F2/Ar. 133 5.3.5.4 Discussion. 135 5.3.6 Conclusion. 137 5.3.7 CrF2 and CrCl2 Investigations. 138 5.3.8 Further Work. 140 References. 142 Chapter 6 Second Row Transition Metal Halides 6.1 Introduction. 149 6.1.1 History of Palladium. 149 viii 6.2 Palladium. 151 6.2.1 Literature Review. 151 6.2.2 Results . 157 6.2.2.1 Computational Studies. 159 6.2.2.1.1 DFT Study of PdFx. 159 6.2.2.2 Pd in 2% F2/Ar. 161 6.2.2.3 Pd in 0.5% F2/Ar. 163 6.2.2.4 Pd in 10% F2/Ar. 169 6.2.2.5 SOTONVIB Calculations. 171 6.2.3 Discussion. 175 6.2.4 Conclusion. 179 6.2.5 Further Work. 180 References. 181 Chapter 7 Third Row Transition Metal Halides 7.1 Introduction. 183 7.1.1 History of Mercury. 183 7.1.2 Mercury in these Experiments. 185 7.2 Literature Review. 188 7.3 Results - Hg and HgF2 in F2/Ar. 190 7.3.1 Early Mass Spectrometry Work. 191 7.3.2 Matrix Isolation IR Spectrometry. 192 7.3.2.1 HgF2 Vaporisation Experiments. 194 7.3.2.2 Mercury Vaporisation Experiments. 197 7.3.2.3 Noble Gas Discharge Lamps. 203 7.3.2.3 Conclusions From IR Experiments. 205 7.3.3 Matrix Isolation UV/Vis Spectroscopy. 207 7.3.3.1 Background and Introduction. 207 7.3.3.2 Experimental Results. 209 ix 7.3.3.2.1 HgF2 Experiments. 210 7.3.3.2.2 Hg Experiments.
Recommended publications
  • Matrix-Isolation FTIR Study of Azidoacetone and Azidoacetonitrile M
    LOW TEMPERATURE PHYSICS VOLUME 29, NUMBER 9–10 SEPTEMBER–OCTOBER 2003 Matrix-isolation FTIR study of azidoacetone and azidoacetonitrile M. Frankowski,* B. S. Fox, A. M. Smith-Gicklhorn, M. K. Beyer, and V. E. Bondybey** Institute of Physical and Theoretical Chemistry, Technical University of Munich, Garching 85747, Germany M. Algarra and M. L. Costa CEFITEC, Department of Physics, Fac. Sciences and Technology, Universidade Nova de Lisboa, Caparica P-2829-516, Portugal P. Rodrigues and M. T. Barros CQFB, Department of Chemistry, Fac. Sciences and Technology, Universidade Nova de Lisboa, Caparica P-2829-516, Portugal M. N. D. S. Cordeiro REQUIMTE, Department of Chemistry, Fac. Sciences, Universidade do Porto, Porto 4169-007, Portugal Fiz. Nizk. Temp. 29, 1140–1146 ͑September–October 2003͒ Azidoacetonitrile (N3CH2CN) and azidoacetone (N3CH2COCH3) are studied by matrix-isolation FTIR spectroscopy in solid neon, argon, and nitrogen. The IR spectra calculated using the density-fuctional theoretical method are discussed in comparison with the experimental data. Significant broadening of the recorded azide bands indicate an awkward fit of these compounds into the solid environment. The strongest absorption is observed for both compounds in the regions of asymmetric and symmetric stretches of the N3 azide group. Strong band splittings in the N3 asymmetric stretch region can be most likely explained by very strong Fermi resonances with the CN stretch and combinations and overtones of the numerous lower- frequency vibrational modes. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1619361͔ INTRODUCTION EXPERIMENTAL Sample preparation Organic azides are useful reagents in many fields.1–3 Their strongly exothermic reactions make them useful as Azidoacetonitrile was synthesized from chloroacetoni- 4 propellants.
    [Show full text]
  • Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Ions
    J. Phys. Chem. A 2000, 104, 3655-3669 3655 Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Ions. 5. PAHs Incorporating a Cyclopentadienyl Ring† D. M. Hudgins,* C. W. Bauschlicher, Jr., and L. J. Allamandola NASA Ames Research Center, MS 245-6, Moffett Field, California 94035 J. C. Fetzer CheVron Research Company, Richmond, California 94802 ReceiVed: NoVember 5, 1999; In Final Form: February 9, 2000 The matrix-isolation technique has been employed to measure the mid-infrared spectra of the ions of several polycyclic aromatic hydrocarbons whose structures incorporate a cyclopentadienyl ring. These include the cations of fluoranthene (C16H10), benzo[a]fluoranthene, benzo[b]fluoranthene, benzo[j]fluoranthene, and benzo- [k]fluoranthene (all C20H12 isomers), as well as the anions of benzo[a]fluoranthene and benzo[j]fluoranthene. With the exception of fluoranthene, which presented significant theoretical difficulties, the experimental data are compared to theoretically calculated values obtained using density functional theory (DFT) at the B3LYP/ 4-31G level. In general, there is good overall agreement between the two data sets, with the positional agreement between the experimentally measured and theoretically predicted bands somewhat better than that associated with their intensities. The results are also consistent with previous experimental studies of polycyclic aromatic hydrocarbon ions. Specifically, in both the cationic and anionic species the strongest ion bands typically cluster in the 1450 to 1300 cm-1 range, reflecting an order-of-magnitude enhancement in the CC stretching and CH in-plane bending modes between 1600 and 1100 cm-1 in these species. The aromatic CH out-of- plane bending modes, on the other hand, are usually modestly suppressed (e 2x - 5x) in the cations relative to those of the neutral species, with the nonadjacent CH modes most strongly affected.
    [Show full text]
  • A MATRIX ISOLATION SPECTROSCOPIC INVESTIGATION of the REACTION PRODUCTS of TRANSITION METAL CENTRES with ETHENE and WATER By
    A MATRIX ISOLATION SPECTROSCOPIC INVESTIGATION OF THE REACTION PRODUCTS OF TRANSITION METAL CENTRES WITH ETHENE AND WATER by MATTHEW G. K. THOMPSON A thesis submitted to the Department of Chemistry in conformity with the requirements for the degree of Doctor of Philosophy Queen’s University Kingston, Ontario, Canada November 2007 Copyright © Matthew Gary Karl Thompson, 2007 Abstract The reaction products of thermally generated atomic V with ethene and ethene isotopomers have been investigated by matrix isolation ultraviolet visible and Fourier transform infrared (FTIR) spectroscopy. When V is deposited into matrices of pure Ar, evidence for V and V2 are present in the UV-visible absorption spectra. Addition of trace amounts of ethene results in the elimination of absorptions due to V2 on deposition, likely due to the formation of … V (C2H4) van der Waals complexes on matrix condensation. Irradiation of matrices containing V and trace C2H4 in Ar, with light corresponding to atomic V electronic excitations, eliminates all UV-visible absorptions due to atomic V in the matrix. Infrared analysis of matrices containing V and C2H4 give evidence for a new product on deposition, consistent with a kinetically formed H-V-C2H3 isomer. Following further irradiation of the matrix, several new products of C-H bond insertion by the metal atom, including additional H-V-C2H3 conformational 2 isomers, and H2V(η -C2H2) products are observed in the infrared spectrum. Additionally, the formation of ethane is evident as a major product immediately following deposition of V + C2H4 + H2O in Ar. The formation of this product is consistent with alkene insertion into the V-H bond of an H-V-OH intermediate, followed by a photo-induced elimination to give C2H6.
    [Show full text]
  • Matrix Isolation and Computational Study of Isodifluorodibromomethane (F2 Cbr-Br): a Route to Br2 Formation in Cf2 Br2 Photolysis
    Bowling Green State University ScholarWorks@BGSU Chemistry Faculty Publications Chemistry 2010 Matrix Isolation and Computational Study of Isodifluorodibromomethane (F2 Cbr-Br): A Route to Br2 Formation in Cf2 Br2 Photolysis Alexander N. Tarnovsky Bowling Green State University, [email protected] Lisa George Aimable Kalume Patrick Z. El-Khoury Scott A. Reid Follow this and additional works at: https://scholarworks.bgsu.edu/chem_pub Part of the Chemistry Commons Repository Citation Tarnovsky, Alexander N.; George, Lisa; Kalume, Aimable; El-Khoury, Patrick Z.; and Reid, Scott A., "Matrix Isolation and Computational Study of Isodifluorodibromomethane (F2 Cbr-Br): A Route to Br2 Formation in Cf2 Br2 Photolysis" (2010). Chemistry Faculty Publications. 26. https://scholarworks.bgsu.edu/chem_pub/26 This Article is brought to you for free and open access by the Chemistry at ScholarWorks@BGSU. It has been accepted for inclusion in Chemistry Faculty Publications by an authorized administrator of ScholarWorks@BGSU. THE JOURNAL OF CHEMICAL PHYSICS 132, 084503 ͑2010͒ Matrix isolation and computational study of isodifluorodibromomethane „F2CBr–Br…: A route to Br2 formation in CF2Br2 photolysis Lisa George,1 Aimable Kalume,1 Patrick Z. El-Khoury,2 Alexander Tarnovsky,2 and ͒ Scott A. Reid1,a 1Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, USA 2Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA ͑Received 29 November 2009; accepted 26 January 2010; published online 22 February 2010͒ ͑ ͒ The photolysis products of dibromodifluoromethane CF2Br2 were characterized by matrix isolation infrared and UV/Visible spectroscopy, supported by ab initio calculations. Photolysis at ͑ϳ ͒ ϳ wavelengths of 240 and 266 nm of CF2Br2 :Ar samples 1:5000 held at 5 K yielded ͑ ͒ iso-CF2Br2 F2CBrBr , a weakly bound isomer of CF2Br2, which is characterized here for the first time.
    [Show full text]
  • Arghya Chakraborty
    Electronic Characterization of Mass-Selected Acyclic, Polycyclic and Oxygenated Hydrocarbons in Neon Matrices INAUGURALDISSERTATION zur Erlangung der Würde eines Doktors der Philosophie vorgelegt der Philosophisch-Naturwissenschaftlichen Fakultät der Universität Basel von Arghya Chakraborty aus Westbengal, Indien Basel, 2016 Originaldokument gespeichert auf dem Dokumentenserver der Universität Basel edoc.unibas.ch 1 Genehmigt von der Philosophisch-Naturwissenschaftlichen Fakultät auf antrag von Dissertationsleiter: Prof. Dr. John. P. Maier Korreferent: Prof. Dr. Stefan Willitsch Basel, 23 Februar 2016 Prof. Dr. J. Schibler Dekan 2 Electronic Characterization of Mass-Selected Acyclic, Polycyclic and Oxygenated Hydrocarbons in Neon Matrices PhD THESIS Of ARGHYA CHAKRABORTY Basel 2016 3 4 Acknowledgements A researcher needs a healthy working atmosphere to be productive. The work and personal life in Basel would not have been so pleasant without the guidance and support of several individuals. First of all, I would like to thank Prof. John Paul Maier for his constant endorsement, supervision and providing world class experimental facilities in laboratory. Beside science, I have learned lots of technical skills from him and hopefully will apply them in my entire career. I am very much thankful to Prof. Stefan Willitsch for being the co-referee of my thesis. Prof. Markus Meuwly is thanked for accepting to be the chair in my PhD defense. Heartiest thank of mine goes to Dr. Jan Fulara for teaching me the essentials of the matrix isolation set-up, sharing his deep knowledge on spectroscopy and helping with his computational skill. Special thanks are also addressed to Dr. Corey Rice for his advices, explanations and experimental ideas. I am highly privileged to him for being the proof reader of my thesis.
    [Show full text]
  • "Carbon-Nitrogen Chain Molecules in the Laboratory and in Interstellar
    CARBON-NITROGEN CHAIN MOLECULES IN THE LABORATORY AND IN INTERSTELLAR MEDIUM BY ROBERT KOŁ OS Institute of Physical Chemistry of the Polish Academy of Sciences Warsaw 2003 ISBN 83-913520-4-8 2 to the memory of my Father 3 4 Preface Science sans conscience n’est que ruine de l’âme. –Rabelais (1532) The simplest and broadest definition of the interstellar matter – “everything but stars” – may be misleading. Is Earth a piece of it? Are humans the interstellar matter, with all material products of the terrestrial civilization? Avoiding the perils of semantics, I will rather use the term in its narrow sense. In what follows, it will primarily be applied to immense clouds of gas and dust, without which the stars would have nothing to be born from, and – when their time comes – nothing to disperse into. It is only 35 years now, since an important, yet largely unnoticed discovery has been made. The interstellar matter was found to be more than just hydrogen, helium, mineral dust, and a small admixture of heavier atoms, their ions, and few simplest diatomics – as was originally believed. In addition to this blend (not very promising for a chemist) the presence of quite complex organic molecules was revealed. By plain chemical standards, some of the compounds given the “interstellar” tag may seem bizzare (or useless), like the largest ones: rod-shaped polyacetylenic nitriles. Still, all these merit our closest attention. If a molecule is abundant enough to show up in the interstellar medium – in spite of present rudimentary detection methods – then it inevitably has to be conceived as one of most important arrangements of atoms in the Galaxy, and possibly also in the entire Universe.
    [Show full text]
  • Chapter 13 Noble-Gas Chemistry
    CHAPTER 13 NOBLE-GAS CHEMISTRY Wojciech Grochala ICM, University of Warsaw, Pawińskiego 5a, 02106 Warsaw Poland and Faculty of Chemistry, University of Warsaw, Pasteur 1, 02093 Warsaw Poland E-mail: [email protected] Leonid Khriachtchev and Markku Räsänen Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki, Finland E-mails: [email protected]; [email protected] Noble-gas chemistry was started in 1962 with the discovery of xenon hexafluoroplatinate followed with a number of compounds binding xenon or krypton. We highlight the classical and more exotic noble-gas compounds and discuss the nature of their bonding starting with strongly bound systems and progressing to weak interactions. Noble-gas hydrides with the common formula HNgY were found in 1995, which led later to the identification of the first argon compound HArF. The formation mechanism of noble-gas hydrides at low temperatures is described in detail followed with a model of bonding. The interactions of the noble- gas hydrides with their surroundings and with complexing molecules are discussed. The chapter ends with known and potential applications of noble gases and with challenges encountered. 1. Introduction The chemistry of noble gases began with a room temperature synthesis of the first xenon compound in the solid state, xenon hexafluoroplatinate 1 (XePtF6 ) by Neil Bartlett. The true and indeed very complex nature of the “XePtF6” compound was confirmed by experiments conducted nearly chapter 13.indd 419 1/27/2011 8:57:08 PM 420 W. Grochala, L. Khriachtchev, and M. Räsänen 40 years after the initial preparation.2 The history of the breaking of the inertness of the noble gases is certainly complex and fascinating, full of many misleading reports, surprises, and ingenuity.3 The chemical bonds between noble gas and other atoms are usually quite fragile due to various redox (electron-transfer) reactions.
    [Show full text]
  • Matrix-Isolation and Computational Studies of Transient Polyhalogenated Intermediates and Weakly-Bound Complexes
    Marquette University e-Publications@Marquette Dissertations (2009 -) Dissertations, Theses, and Professional Projects MATRIX-ISOLATION AND COMPUTATIONAL STUDIES OF TRANSIENT POLYHALOGENATED INTERMEDIATES AND WEAKLY-BOUND COMPLEXES. AIMABLE KALUME Marquette University Recommended Citation KALUME, AIMABLE, "MATRIX-ISOLATION AND COMPUTATIONAL STUDIES OF TRANSIENT POLYHALOGENATED INTERMEDIATES AND WEAKLY-BOUND COMPLEXES." (2013). Dissertations (2009 -). Paper 274. http://epublications.marquette.edu/dissertations_mu/274 MATRIX-ISOLATION AND COMPUTATIONAL STUDIES OF TRANSIENT POLYHALOGENATED INTERMEDIATES AND WEAKLY-BOUND COMPLEXES. by Aimable KALUME A Dissertation submitted to the Faculty of the Graduate School, Marquette University, in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. Milwaukee, Wisconsin May 2013 ABSTRACT MATRIX-ISOLATION AND COMPUTATIONAL STUDIES OF TRANSIENT POLYHALOGENATED INTERMEDIATES AND WEAKLY-BOUND COMPLEXES. Aimable KALUME Marquette University, 2013 As time goes by and new innovations are brought up to improve living conditions, the human impact on the environment becomes more significant. It has been shown that man-made halogenated compounds play a key role in many real-world chemical processes. For example, in combustion, these compounds are used as fire retardant agents, and in atmospheric chemistry, they initiate ozone depletion reactions.[1-4] However little is known about the mechanisms governing these processes and many intermediates involved in these processes have been elusive to researchers for diverse reasons such as short lifetime and difficulty in distinguishing products from parents molecules. The studies compiled in this work are focused on exploring the photochemical behavior of various intermediates derived from polyhalogenated compounds. These intermediates are trapped in inert rigid matrix and characterized by using IR, UV/Vis spectroscopy supported by computational methods.
    [Show full text]
  • Sub-Nanometer Optical Linewidth of Thulium Atoms in Rare Gas Crystals
    Sub-nanometer optical linewidth of thulium atoms in rare gas crystals Vinod Gaire, Chandra S. Raman, and Colin V. Parker∗ School of Physics, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA (Dated: January 24, 2019) Abstract We investigate the 1140 nm magnetic dipole transition of thulium atoms trapped in solid argon and neon. These solids can be straightforwardly grown on any substrate at cryogenic temperatures, making them prime targets for surface sensing applications. Our data are well described by a splitting of the single vacuum transition into three components in both argon and neon, with each component narrower than the 0.8 nm spectrometer resolution. The lifetime of the excited states is 14.6(0.5) ms in argon and 27(3) ms in neon, shorter than in vacuum or in solid helium. We also collected visible laser-induced fluorescence spectroscopy showing broader emission features in the range of 580-600 nm. The narrow infrared features in particular suggest a range of possible applications. arXiv:1901.07630v1 [physics.atom-ph] 22 Jan 2019 1 INTRODUCTION Isolated atoms are narrow-linewidth optical emitters that make very precise clocks [1{ 3] and sensors [4]. However, realizing this isolation requires that the density be low and the atoms be far from surfaces. On the other hand, atoms or atom-like defects in solid systems retain many of the magnetic and optical properties of free atoms, including in some cases long spin coherence times and narrow homogeneous linewidths[5{8]. Unlike isolated atoms, these systems are confined in their hosts, which affords a wealth of opportunities for quantum sensing and quantum control at very short length scales (1-10 nm) proximate to surfaces.
    [Show full text]
  • Complexes of Glycolic Acid with Nitrogen Isolated in Argon Matrices
    molecules Article Complexes of Glycolic Acid with Nitrogen Isolated in Argon Matrices. I. Structures and Thermal Effects Iwona Kosendiak 1, Jussi M.E. Ahokas 2 , Justyna Krupa 1 , Jan Lundell 2,* and Maria Wierzejewska 1,* 1 Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw, Poland 2 Department of Chemistry, University of Jyvaskyla, P.O.Box 35, 40014 Jyvaskyla, Finland * Correspondence: jan.c.lundell@jyu.fi (J.L.); [email protected] (M.W.); Tel.: +358-40-744-5270 (J.L.); +48-71-375-7332 (M.W.) Received: 29 July 2019; Accepted: 5 September 2019; Published: 7 September 2019 Abstract: Molecular complexes between glycolic acid and nitrogen were studied in a low-temperature argon matrix with FTIR spectroscopy, and supported by MP2 and BLYPD3 calculations. The calculations indicate 11 and 10 stable complex structures at the MP2 and BLYPD3 levels of theories, respectively. However, only one hydrogen-bonded complex structure involving the most stable SSC conformer of glycolic acid was found experimentally, where the nitrogen molecule is bound with the carboxylic OH group of the SSC conformer. The complex shows a rich site structure variation upon deposition of the matrix in different temperatures and upon annealing experiments, which provide interesting prospects for site-selective chemistry. Keywords: hydrogen bond; matrix isolation; carboxylic acid; computational chemistry; vibrational spectroscopy 1. Introduction Hydrogen bonding is a significant non-covalent interaction that plays an important role in many areas of biology and chemistry [1,2]. Weakly bound molecular complexes with hydrogen bond or van der Waals interactions are frequently encountered in atmospheric chemistry and are known to affect both chemical and photochemical processes [3–5].
    [Show full text]
  • Low Temperature Matrix-Isolation and Solid State Vibrational Spectra of Tetrazole
    Low temperature matrix-isolation and solid state vibrational spectra of tetrazole Susana C. S. Bugalho,a Ermelinda M. S.MacÓ oü as,a M. Lurdes S. Cristianob and Rui Fausto*a a Department of Chemistry (CQC), University of Coimbra, 3004-535 Coimbra, Portugal b Department of Chemistry (UIQB), University of Algarve, 8000-117 Faro, Portugal Received 12th April 2001, Accepted 8th June 2001 First published as an Advance Article on the web 19th July 2001 \ Infrared spectra of tetrazole(CN4H2) isolated in an argon matrix (T 10 K) and in the solid state (at room temperature) were investigated. In the crystalline phase, tetrazole exists in its 1H-tautomeric form and new assignments of the vibrational spectra (both infrared and Raman) of this phase are presented. The infrared spectrum of the matrix-isolated monomeric form of tetrazole is now reported and assigned for the Ðrst time, showing essentially the expected signature of the 2H-tetrazole tautomer. From relative intensities of the infrared bands ascribable to the two tautomers, the amount of the 1H-tautomer in the argon matrix was estimated to be ca. 10% of the most stable tautomer. Assuming that gas-phase relative populations of the two tautomers could be efficiently trapped in the argon matrix during deposition, the energy di†erence between \ ^ ~1 1H- and 2H-tetrazole(*E1Hh2H) was then obtained. The experimental value,*E1Hh2H 6.95 1.50 kJ mol , now determined for the Ðrst time, compares fairly well with the theoretical predictions for the molecule in vacuum (e.g., the zero point vibrational energy corrected energy di†erence obtained at the B3LYP/6È31G* level of theory is 9.96 kJ mol~1).
    [Show full text]
  • A Study of Matrix Isolated Ions by Electron Spin Resonance
    A STUDY OF MATRIX ISOLATED IONS BY ELECTRON SPIN RESONANCE SPECTROSCOPY A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy in Chemistry in the University of Canterbury By A.J. McKinley University of Canterbury 1985 Except as provided by the Copyright Act 1994, no part of this publication may be reproduced or stored in a retrieval system in any form or by any means without the prior written permission of the copyright owner, A.J. McKinley. http://hdl.handle.net/10092/9393 A STUDY OF MATRIX ISOLATED IONS BY ELECTRON SPIN RESONANCE SPECTROSCOPY A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy in Chemistry in the University of Canterbury by A.J. McKinley University of Canterbury 1985 SCIF.NCES Lt6AAR,'{ THESIS COf'':~ TO MY PARENTS PUBLICATIONS The following paper relating to research described in this thesis has been accepted for publication. "The ESR observation of 14NH3+ and lSNH3+ trapped in an argon matrix at 12K." A.J. McKinley, R.F.C. Claridge, P.W. Harland accepted for publication in Chemical Physics. A reprint of this paper is included inside the back cover of this thesis. PAGE ABSTRACT 01 CHAPTER I INTRODUCTION 03 1.1 Introduction to ESR spectroscopy 05 1.2 Review of the literature 11 1.3 General introduction to experimental apparatus 19 CHAPTER II ION SOURCE DEVELOPMENT 21 2.1 Operation of the charged particle 21 oscillator ion source 2.2 Testing of the charged particle 26 oscillator ion source 2.3 Gas phase ESR studies 29 2.4 Cyclotron
    [Show full text]