Chapter One IR-VUV Photoionization Spectroscopy
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On the Photoionization of Large Molecules
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector ________ ~~__ On the Photoionization of Large Molecules C. H. Becker and K. J. Wu* Molecular Phvxics L‘tbordtorv, SRI Irlternatmnal, Menlo Park. ialifornia, USA There is no apparent limit to the size of a molecule for which photoionization can occur. It is argued that it is difficult to obtain useful photoionization mass spectra of peptides (above - 2000 u), proteins, and oligonucleotides, because of the high internal energy of these polar molecules as a result of the desorption event and because vibrationally excited radical cations readily fragment. Evidence to support this hypothesis is presented from the 1%nm single-photon ionization 61’1) mass spectra of the cyclic decapeptide gramicidin S and of fullerencs, from null SPI results with the linear peptides substance P and gramicidin D and oligonucleotides, and from a variety of data found in the literature. The literature data include mass spectra from jet-cooled peptides, perfluorinated polyethers, collisional ioniza- tion of small neutral peptides, and the ultraviolet photoelectron spectroscopy of polymeric solids. (1 Am Sot Mass Spcctrom 1995, 6, 883-888) uch recent effort in mass spectrometry has (MALD), peptides and proteins show significant de- been directed toward the analysis of peptides grees of metastable decay that increases with the mass M and proteins [l, 21, DNA [3, 41, and other of the molecule [ll]. Even for the MALD technique, large biopolymers. Successful analytical approaches to considered currently to be the “gentlest” of all stimu- date have used the direct ionization associated with lated desorption techniques in that it permits observa- the desorption process, especially with laser desorp- tion of the quasimolecular ions of large proteins and tion. -
Improved Treatment of the Photoionization Process in the Laser Induced Optical Breakdown in the Laser Tissue
U.P.B. Sci. Bull., Series A, Vol. 81, Iss. 4, 2019 ISSN 1223-7027 IMPROVED TREATMENT OF THE PHOTOIONIZATION PROCESS IN THE LASER INDUCED OPTICAL BREAKDOWN IN THE LASER TISSUE Violeta PETROVIĆ1 and Hristina DELIBAŠIĆ1 The development of laser technology led to the discovery that laser-living tissue (cells) interactions have significant biomedical applications and can be used to perform precise surgical procedures of 'water-like' tissues (such as the eye). When the focus is located within transparent biological cells and tissues, nonlinear absorption processes initiate a laser induced optical breakdown. The threshold for breakdown is defined by a certain critical free electron density. An in depth understanding of these processes orientated our theoretical research to the development of rate equations describing electron density growth in a transparent biological media exposed to a femtosecond laser pulse. In order to provide an accurate theoretical model and to predict damage occurrence, we took into account the losses through diffusion of electrons out of the focal volume, cascade ionization and the model of photoionization based on the standard Keldysh and ADK theory. Keywords: laser-induced breakdown, avalanche process, Keldysh theory. 1. Introduction The advent of high-power lasers opened the door for a wide range of laser application [1, 2, 3]. The effect known as the breakdown is a very important topic due to its role in laser applications. Breakdown is an effect which can be produced by high electric field strengths. This means that after a spark the medium becomes electrically conducting. Laser-induced breakdown (LIB) can occur in any media: solid, liquid, or gas. -
Assessment of Portable HAZMAT Sensors for First Responders
The author(s) shown below used Federal funds provided by the U.S. Department of Justice and prepared the following final report: Document Title: Assessment of Portable HAZMAT Sensors for First Responders Author(s): Chad Huffman, Ph.D., Lars Ericson, Ph.D. Document No.: 246708 Date Received: May 2014 Award Number: 2010-IJ-CX-K024 This report has not been published by the U.S. Department of Justice. To provide better customer service, NCJRS has made this Federally- funded grant report available electronically. Opinions or points of view expressed are those of the author(s) and do not necessarily reflect the official position or policies of the U.S. Department of Justice. Assessment of Portable HAZMAT Sensors for First Responders DOJ Office of Justice Programs National Institute of Justice Sensor, Surveillance, and Biometric Technologies (SSBT) Center of Excellence (CoE) March 1, 2012 Submitted by ManTech Advanced Systems International 1000 Technology Drive, Suite 3310 Fairmont, West Virginia 26554 Telephone: (304) 368-4120 Fax: (304) 366-8096 Dr. Chad Huffman, Senior Scientist Dr. Lars Ericson, Director UNCLASSIFIED This project was supported by Award No. 2010-IJ-CX-K024, awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. The opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect those of the Department of Justice. This document is a research report submitted to the U.S. Department of Justice. This report has not been published by the Department. Opinions or points of view expressed are those of the author(s) and do not necessarily reflect the official position or policies of the U.S. -
Technical Application Note
Compact Rugged Spectrometers - A Universe of Spectroscopy Systems Technical Application Note Vibrational Spectroscopy: Infrared vs. Raman StellarNet, Inc. Tampa, Fl USA Tony Rizzuto, PhD April 12, 2017 Vibrational spectroscopies are integral in analyzing some of the most fundamentally important processes in physical chemistry: molecular vibrations. While there are many different experimental techniques used to analyze those vibrations, most are variations of the “Big Two,” FTIR and Raman scattering spectroscopies. This article aims to analyze the benefits and drawbacks of each of the “Big Two,” with the hope that it helps one choose the correct technique for one’s research interests. 1. What are the “Big Two?” Fourier Transform Infrared Spectroscopy Raman spectroscopy relies on inelastic (FTIR) is a simple absorption measurement scattering phenomenon that probes the where the detector measures the molecular vibration. Where FTIR will use a absorbance of infrared radiation by the broadband IR source, Raman spectroscopy sample. Each sample will absorb different typically uses a narrow-band, amounts of each frequency resulting in a monochromatic light source in order to “chemical fingerprint” that is the FTIR excite the vibrations of the molecule in your spectrum. sample. 2. Selection Rules: What molecular vibrations are being probed? Imagining a molecular bond vibration with the traditional ball and spring model (Figure 1a) and its resultant harmonic oscillator depiction (Figure 1b) allows us to calculate the selection rules for vibrational transitions to be = 1. However, that does not tell the whole story. In order to truly differentiate FTIR from Raman Spectroscopy, we must think about it on a molecular level. Compact Rugged Spectrometers - A Universe of Spectroscopy Systems Technical Application Note A B Figure 1: A. -
Direct Measurement of Electron Numbers Created at Near-Infrared Laser-Induced Ionization of Various Gases
Direct Measurement of Electron Numbers Created at Near-Infrared Laser-Induced Ionization of Various Gases A. Sharma1, M. N. Slipchenko1, K. A. Rahman1, M. N. Shneider2, and A. Shashurin1 1 Purdue University, West Lafayette, IN, USA 2 Princeton University, Princeton, NJ, USA Abstract In this work, we present temporally resolved measurements of electron numbers created at photoionization of various gases by femtosecond laser pulse at 800 nm wavelength. The experiments were conducted in O2, Xe, Ar, N2, Kr and CO at room temperature and atmospheric pressure. Elastic microwave scattering was used to directly measure the electron numbers. Numbers of electrons in the range 3108 to 31012 electrons were produced by the laser pulse energies 100-700 J. After the laser pulse, plasma decayed on the time scale varied from 1 to 40 ns depending on the gas type and governed by two competing processes, namely, the creation of new electrons from ionization of the metastable atoms and loss of the electrons due to dissociative recombination and attachment to oxygen. Introduction Broad research history of the laser-induced plasmas is related to studies of various nonlinear effects at laser beam propagation such as laser pulse filamentation, laser beam collapse, self-trapping, dispersion, modulation instability, pulse splitting etc.1,2,3,4,5 These effects are various manifestations of the combined action of focusing Kerr nonlinearity (optical Kerr effect) and defocusing nonlinearity due to plasmas. Nowadays laser-induced plasmas find very wide application for plasma-assisted combustion, combustion diagnostics, laser-induced breakdown spectroscopy etc. 5 Conventional techniques for diagnostics of laser-induced plasmas pose detrimental 16 17 - limitations. -
Photoionization
DLJSRF/R 1 fh ~ · DARESBURY SYNCHROTRON RADIATION LECTURE NOTE SERIES No.1 PHOTOIONIZATION by C. Bottcher Science Research Council DARESBURY LABORATORY Daresbury, Warrington, WA4 4AD DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. © SCIENCE RESEARCH COUNCIL 1974 Enquiries about copyright and reproduction should be addressed to : The Librarian, Daresbury Laboratory, Daresbury, Warrington, WA44AD. IMPORTANT The SRC does not accept any responsibility for loss or damage arising from the use of information contained in any of its reports or in any communication about its tests or investigations. Printed by McCorquodale Printers Ltd., NAwton-IA-Willow,;. M ersey side. DARESBURY SYNCHROTRON RADIATION LECTURE NOTE SERIES No.1 PHOTOIONIZATION C. Bottcher Department of Theoretical Physics University of Manchester Notes on a series of lectures given at Daresbury Laboratory, November 1973 Science Research Council DARESBURY LABORATORY 1974 iWASlER FOREWORD These lectures were given in November 1973 to experimental physicists using the Synchrotron Radiation Facility at Daresbury. -
Neutron Vibrational Spectroscopy
Neutron Vibrational Spectroscopy A.J. (Timmy) Ramirez-Cuesta Luke L. Daemen Yongqiang Cheng Spallation Neutron Source Oak Ridge National Laboratory ORNL is managed by UT-Battelle for the US Department of Energy The S(Q,w) Map w=0 Elastic Scattering Diffraction Structural Information 2 "Let there be light" 3 4 How to measure INS (1) Direct Geometry Instrumentation 4000 3500 Direct geometry instruments 3000 ) 1 - m measure Q trajectory is c ( 2500 r e f determined by the angle s n 2000 a r t and energy transfer. y g r 1500 e n Examples: ARCS, CNCS, E HYSPEC, SEQUIOA 1000 500 0 0 10 20 30 Momentum transfer (A-1) ) . U . A ( y t i s n e L t 2 n I Incident neutron beam is 0 10 20 30 40 50 60 70 Energy (meV) s monochromatic t n u o c determining the incident n o r t u Distance energy E1. e N That determines T1. We L1 12000 13000 14000 15000 16000 measure the ToF and we ToF (ms) can work out T2. Resolution is almost constant in units of Ei time 5 VISION: a high throughput spectrometer for neutron vibrational spectroscopy Yongqiang Cheng, Luke Daemen, A.J. (Timmy) Ramirez-Cuesta Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37931 USA VISION offers users a variety of sample environments How to measure INS (2) Polybenzene nanothreads synthesized at high pressure: single nanothreads VISION is best thought of as and experimental/computational capabilities: the neutron analogue of a Structural inference through modeling of vibrational spectra Indirect Geometry Instrumentation Raman spectrometer. -
Photoionization of Kcs Molecule: Origin of the Structured Continuum?
atoms Article Photoionization of KCs Molecule: Origin of the Structured Continuum? Goran Pichler 1,*, Robert Beuc 1, Jahja Kokaj 2, David Sarkisyan 3, Nimmy Jose 2 and Joseph Mathew 2 1 Institute of Physics, 10000 Zagreb, Croatia; [email protected] 2 Department of Physics, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait; [email protected] (J.K.); [email protected] (N.J.); [email protected] (J.M.) 3 Institute for Physical Research, Armenian Academy of Science, Ashtarak 0203, Armenia; [email protected] * Correspondence: [email protected]; Tel.: +385-91-469-8826 Received: 30 April 2020; Accepted: 26 May 2020; Published: 28 May 2020 Abstract: We report the experimental observation of photoionization bands of the KCs molecule in the deep ultraviolet spectral region between 200 and 420 nm. We discuss the origin of observed photoionization bands as stemming from the absorption from the ground state of the KCs molecule to the excited states of KCs+ molecule for which we used existing potential curves of the KCs+ molecule. An alternative explanation relies on the absorption from the ground state of the KCs molecule to the doubly excited states of the KCs** molecule, situated above the lowest molecular state of KCs+. The relevant potential curves of KCs** are not known yet, but all those KCs** potential curves are certainly autoionizing. However, these two photoionization pathways may interfere resulting in a special interference structured continuum, which is observed as complex bands. Keywords: photoionization; alkali molecule; autoionization of molecule; heteronuclear molecule 1. Introduction High-temperature alkali mixtures possessing high densities of constituents enable observation of the characteristic bands of mixed alkali molecules [1]. -
Femtosecond Time-Resolved Observation of Butterfly Vibration In
www.nature.com/scientificreports OPEN Femtosecond time-resolved observation of butterfy vibration in electronically excited Received: 7 June 2017 Accepted: 11 October 2017 o-fuorophenol Published: xx xx xxxx Fengzi Ling1,2, Shuai Li1,2, Xinli Song1,2, Yanmei Wang1,2, Jinyou Long1,2 & Bing Zhang 1,2 The butterfy vibration during the hydrogen tunneling process in electronically excited o-fuorophenol has been visualized in real time by femtosecond time-resolved ion yield spectroscopy coupled with time-resolved photoelectron imaging technique. A coherent superposition of out-of-plane C–F butterfy motions is prepared in the frst excited electronic state (S1). As the C–F bond vibrates with respect to the aromatic ring, the nuclear geometry varies periodically, leading to the corresponding variation in the photoionization channel. By virtue of the more favorable ionization probability from the nonplanar minimum via resonance with the Rydberg states, the evolution of the vibrational wave packet is manifested as a superimposed beat in the parent-ion transient. Moreover, time-resolved photoelectron spectra ofer a direct mapping of the oscillating butterfy vibration between the planar geometry and nonplanar minimum. The beats for the photoelectron peaks originating from the planar geometry are out of phase with those from the nonplanar minimum. Our results provide a physically intuitive and complete picture of the oscillatory fow of energy responsible for the coherent vibrational motion on the excited state surface. Ultrafast molecular vibration is one of the fundamental motions that characterize chemical bonding and decide reaction dynamics at the molecular level1–3. Over the past few decades, frequency-resolved spectroscopies such as infrared and Raman spectra4 and resonant two-photon ionization (R2PI) spectroscopy5 have devoted to pro- viding detailed spectroscopic data about molecular vibration. -
Photoionization and Excitation of Free Variable Size Van Der Waals Clusters in the Inner Shell Regime
Photoionization and Excitation of Free Variable Size van der Waals Clusters in the Inner Shell Regime Dissertation zur Erlangung des naturwissenschaftlichen Doktorgrades der Bayerischen Julius-Maximilians-Universit¨at Wurzburg¨ vorgelegt von Ioana Lavinia Bradeanu aus Bucharest Wurzburg¨ 2005 Eingereicht am: bei der Fakult¨at fur¨ Chemie und Pharmazie 1. Gutachter: 2. Gutachter: der Dissertation 1. Prufer:¨ 2. Prufer:¨ 3. Prufer:¨ des Offentlichen¨ Promotionskolloquiums Tag der mundlichen¨ Prufung:¨ Doktorurkunde ausgeh¨andigt am: Abstract Photoionization from core levels provides element-specific information on the electronic structure of atoms, molecules, and condensed matter. Post-collision interaction (PCI) is investigated in free, variable size krypton and argon clusters near the Kr 3d- and Ar 2p-ionization energies. Photoionization of free Van der Waals clusters is reported using zero kinetic energy (ZEKE) photoelectron spectroscopy in the Ar 2p, Ne 1s, Kr 3d and N 1s excitation regime. ZEKE photoelectron spectroscopy is used as an experimental technique for investigating the core ionization process as a function of cluster size. It is found that the asymmetry, which is a consequence of PCI, is characteristically smaller for clusters than for isolated atoms. Moreover, there is less asymmetry for bulk-sites than for surface-sites in variable size rare gas clusters. The emission of ultraviolet fluorescence from variable size argon clusters is investigated in the Ar 2p-excitation regime (240–270 eV). The results are assigned in terms of plausi- ble relaxation processes occurring in the 2p-excitation regime. This implies that charge separation mechanisms are active, which occur after electronic relaxation of the core hole. Besides electron impact ionization within clusters caused by Auger electrons, the inter- atomic Coulombic decay (ICD) mechanism appears to be a plausible way to rationalize the experimental findings. -
All-Digital Histopathology by Infrared-Optical Hybrid Microscopy
All-digital histopathology by infrared-optical hybrid microscopy Martin Schnella, Shachi Mittala,b, Kianoush Falahkheirkhaha,c, Anirudh Mittala,b, Kevin Yeha,b, Seth Kenkela,d, Andre Kajdacsy-Ballae, P. Scott Carneyf, and Rohit Bhargavaa,b,c,d,g,h,i,1 aBeckman Institute for Advanced Science and Technology, University of Illinois at Urbana–Champaign, Urbana, IL 61801; bDepartment of Bioengineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801; cDepartment of Chemical and Biomolecular Engineering, University of Illinois at Urbana– Champaign, Urbana, IL 61801; dDepartment of Mechanical Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801; eDepartment of Pathology, University of Illinois at Chicago, Chicago, IL 60612; fThe Institute of Optics, University of Rochester, Rochester, NY 14620; gCancer Center at Illinois, University of Illinois at Urbana–Champaign, Urbana, IL 61801; hDepartment of Electrical and Computer Engineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801; and iDepartment of Chemistry, University of Illinois at Urbana–Champaign, Urbana, IL 61801 Edited by Christian Huck, University of Innsbruck, Innsbruck, Austria, and accepted by Editorial Board Member John A. Rogers December 20, 2019 (received for review July 19, 2019) Optical microscopy for biomedical samples requires expertise in fidelity imaging in both point-scanning (15) and wide-field (16–19) staining to visualize structure and composition. Midinfrared (mid-IR) modalities, IR pixel sizes are ∼100-fold larger than those easily spectroscopic imaging offers label-free molecular recording and achieved in visible microscopy, and data acquisition speed is still virtual staining by probing fundamental vibrational modes of three to four orders of magnitude slower than in visible imaging molecular components. -
Time-Discretized Extreme and Vacuum Ultraviolet Spectroscopy of Spark
Journal of Physics D: Applied Physics PAPER Related content - Photoionization capable, extreme and Time-discretized extreme and vacuum ultraviolet vacuum ultraviolet emission in developing low temperature plasmas in air J Stephens, A Fierro, S Beeson et al. spectroscopy of spark discharges in air, N2 and O2 - A nanosecond surface dielectric barrier discharge at elevated pressures: time- To cite this article: D Trienekens et al 2016 J. Phys. D: Appl. Phys. 49 035201 resolved electric field and efficiency of initiation of combustion I N Kosarev, V I Khorunzhenko, E I Mintoussov et al. - Optical emission spectroscopy study in the View the article online for updates and enhancements. VUV–VIS regimes of a developing low- temperature plasma in nitrogen gas A Fierro, G Laity and A Neuber Recent citations - Guided ionization waves: The physics of repeatability XinPei Lu and Kostya (Ken) Ostrikov - Practical considerations for modeling streamer discharges in air with radiation transport J Stephens et al - Photoionization capable, extreme and vacuum ultraviolet emission in developing low temperature plasmas in air J Stephens et al This content was downloaded from IP address 129.118.3.25 on 05/09/2018 at 18:26 IOP Journal of Physics D: Applied Physics Journal of Physics D: Applied Physics J. Phys. D: Appl. Phys. J. Phys. D: Appl. Phys. 49 (2016) 035201 (5pp) doi:10.1088/0022-3727/49/3/035201 49 Time-discretized extreme and vacuum 2016 ultraviolet spectroscopy of spark © 2016 IOP Publishing Ltd discharges in air, N2 and O2 JPAPBE D Trienekens1,2,