Imaging photoelectron photoion coincidence spectroscopy with velocity focusing electron optics

Bodi, Andras; Johnson, Melissa; Gerber, T.; Gengeliczki, Zsolt; Sztáray, Bálint; Baer, Tomas

doi:10.1063/1.3082016

Cited by 198 publications

(236 citation statements)

References 41 publications

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“…Using absolute, total vacuum-UV absorption cross section data from Au et al [24], quantum yields for anion production can also be determined. [44]. There is no similarity between this spectrum and any of the three anion yields over this energy range.…”

Section: Ion-pair Spectramentioning

confidence: 85%

Vacuum-UV negative photoion spectroscopy of CH₄

Rogers¹,

Tuckett²,

Dunn³

et al. 2010

Molecular Physics

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_________________________________________________Using synchrotron radiation in the range 12−35 eV, negative ions are detected by mass spectrometry following vacuum-UV photoexcitation of methane. Ion yields for H − , CH − and CH 2 − are recorded, the spectra of CH − and CH 2 − for the first time. All ions display a linear dependence of signal with pressure, showing that they arise from unimolecular ion-pair dissociation. Cross sections for ion-pair formation are put onto an absolute scale by calibrating the signal strengths with those of F − from SF 6 and CF 4 .Following normalisation to total vacuum-UV absorption cross sections, quantum yields for anion production are reported. There is a major discrepancy in the H − cross section with an earlier measurement, which remains unresolved. The anions arise from both direct and indirect ion-pair mechanisms. increasing with increasing v in the ν 1 (a 1 ) vibrational ladder. They are the first direct measurement of an upper value to the dissociation rate of these levels into fragment ions.___________________________________________________

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Section: Ion-pair Spectramentioning

confidence: 85%

Vacuum-UV negative photoion spectroscopy of CH₄

Rogers¹,

Tuckett²,

Dunn³

et al. 2010

Molecular Physics

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“…The main advantage of this technique is the soft ionization, which facilitates the timely detection, identification and quantification of transient species during pyrolysis and combustion. Furthermore, imaging photoelectron photoion coincident spectroscopy was reported as one of the most powerful tools for isomer-selective identification of complex reactive intermediates [86]. The thermal decomposition of dimethyl methyl phosphate (DMMP) was recently reported, using VUV photoionization [87].…”

Section: Vuv Photoionization Coupled With Time Of Flight Msmentioning

confidence: 99%

An Overview of Mode of Action and Analytical Methods for Evaluation of Gas Phase Activities of Flame Retardants

et al. 2015

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Abstract:The latest techniques used to prove, describe and analyze the gas phase activity of a fire retardant used in polymeric materials are briefly reviewed. Classical techniques, such as thermogravimetric analysis or microscale combustion calorimetry, as well as complex and advanced analytical techniques, such as modified microscale combustion calorimeter (MCC), molecular beam mass spectroscopy and vacuum ultra violet (VUV) photoionization spectroscopy coupled with time of flight MS (TOF-MS), are described in this review. The recent advances in analytical techniques help not only in determining the gas phase activity of the flame-retardants but also identify possible reactive species responsible for gas phase flame inhibition. The complete understanding of the decomposition pathways and the flame retardant activity of a flame retardant system is essential for the development of new eco-friendly-tailored flame retardant molecules with high flame retardant efficiency.

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“…The resident imaging photoelectron photoion coincidence (iPEPICO) spectrometer combines a Wiley-McLaren time-of-flight (TOF) mass spectrometer 20 and a velocity map imaging electron spectrometer. The pure sample was introduced into the chamber through an effusive source at room temperature, with typical pressures in the experimental chamber being 2-4 × 10 −6 mbar during measurement.…”

Section: A Experimentalmentioning

confidence: 99%

Vibrational and electronic excitations in fluorinated ethene cations from the ground up

Harvey

Hemberger

Bodi

et al. 2013

The Journal of Chemical Physics

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Valence threshold photoelectron spectra of four fluorinated ethenes; C 2 H 3 F, 1,1-C 2 H 2 F 2 , C 2 HF 3 , and C 2 F 4 were recorded at the Swiss Light Source with 0.002 eV resolution. The adiabatic ionization energies were found to be 10.364 ± 0.007, 10.303 ± 0.005, 10.138 ± 0.007, and 10.110 ± 0.009 eV, respectively. The electronic ground state of each cation shows well-resolved multi-component vibrational progressions, the dominant transitions being in the C=C stretching mode. Density functional theory based Franck-Condon simulations are used to model the vibrational structure and assign the spectra, sometimes revising previous assignments. An additional vibrational progression in the first photoelectron band of 1,1-C 2 H 2 F 2 indicates that the ground electronic state of the molecular ion is no longer planar. It is shown that ab initio vibrational frequencies together with the observed vibrational spacings do not always suffice to assign the spectra. In addition to symmetry rules governing the transitions, it is often essential to consider the associated Franck-Condon factors explicitly. Ionization to higher lying excited valence electronic states were also recorded by threshold ionization up to 23 eV photon energy. Equation-of-motion coupled cluster with single and double substitutions for ionization potential (EOM-IP-CCSD/cc-pVTZ) calculations confirmed historic electronic state assignments, and untangled the ever more congested spectra with increasing F-substitution. Previous attempts at illuminating the intriguing dissociative photoionization mechanism of fluorinated ethenes are reconsidered in view of new computational and experimental results. We show how non-statistical F-atom loss from C 2 H 3 F + is decoupled from the ground state dissociation dynamics in the energy range of itsC state. Both the statistical and the non-statistical dissociation processes are mediated by a plethora of conical intersections.

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Imaging photoelectron photoion coincidence spectroscopy with velocity focusing electron optics

Cited by 198 publications

References 41 publications

Vacuum-UV negative photoion spectroscopy of CH₄

Vacuum-UV negative photoion spectroscopy of CH₄

An Overview of Mode of Action and Analytical Methods for Evaluation of Gas Phase Activities of Flame Retardants

Vibrational and electronic excitations in fluorinated ethene cations from the ground up

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Imaging photoelectron photoion coincidence spectroscopy with velocity focusing electron optics

Cited by 198 publications

References 41 publications

Vacuum-UV negative photoion spectroscopy of CH4

Vacuum-UV negative photoion spectroscopy of CH4

An Overview of Mode of Action and Analytical Methods for Evaluation of Gas Phase Activities of Flame Retardants

Vibrational and electronic excitations in fluorinated ethene cations from the ground up

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Product

Resources

About

Vacuum-UV negative photoion spectroscopy of CH₄

Vacuum-UV negative photoion spectroscopy of CH₄