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Title: Zero kinetic energy photoelectron spectroscopy of triphenylene

Abstract

We report vibrational information of both the first electronically excited state and the ground cationic state of jet-cooled triphenylene via the techniques of resonantly enhanced multiphoton ionization (REMPI) and zero kinetic energy (ZEKE) photoelectron spectroscopy. The first excited electronic state S{sub 1} of the neutral molecule is of A{sub 1}′ symmetry and is therefore electric dipole forbidden in the D{sub 3h} group. Consequently, there are no observable Franck-Condon allowed totally symmetric a{sub 1}′ vibrational bands in the REMPI spectrum. All observed vibrational transitions are due to Herzberg-Teller vibronic coupling to the E′ third electronically excited state S{sub 3}. The assignment of all vibrational bands as e′ symmetry is based on comparisons with calculations using the time dependent density functional theory and spectroscopic simulations. When an electron is eliminated, the molecular frame undergoes Jahn-Teller distortion, lowering the point group to C{sub 2v} and resulting in two nearly degenerate electronic states of A{sub 2} and B{sub 1} symmetry. Here we follow a crude treatment by assuming that all e′ vibrational modes resolve into b{sub 2} and a{sub 1} modes in the C{sub 2v} molecular frame. Some observed ZEKE transitions are tentatively assigned, and the adiabatic ionization threshold is determined to be 63 365more » ± 7 cm{sup −1}. The observed ZEKE spectra contain a consistent pattern, with a cluster of transitions centered near the same vibrational level of the cation as that of the intermediate state, roughly consistent with the propensity rule. However, complete assignment of the detailed vibrational structure due to Jahn-Teller coupling requires much more extensive calculations, which will be performed in the future.« less

Authors:
; ;  [1]
  1. Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)
Publication Date:
OSTI Identifier:
22311292
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 140; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALLOCATIONS; CATIONS; COMPARATIVE EVALUATIONS; DENSITY FUNCTIONAL METHOD; ELECTRIC DIPOLES; ELECTRONS; INTERMEDIATE STATE; JAHN-TELLER EFFECT; KINETIC ENERGY; MOLECULES; PHOTOELECTRON SPECTROSCOPY; PHOTOIONIZATION; SIMULATION; SPECTRA; TIME DEPENDENCE; TRIPHENYLENE; VIBRATIONAL STATES

Citation Formats

Harthcock, Colin, Zhang, Jie, and Kong, Wei. Zero kinetic energy photoelectron spectroscopy of triphenylene. United States: N. p., 2014. Web. doi:10.1063/1.4884905.
Harthcock, Colin, Zhang, Jie, & Kong, Wei. Zero kinetic energy photoelectron spectroscopy of triphenylene. United States. https://doi.org/10.1063/1.4884905
Harthcock, Colin, Zhang, Jie, and Kong, Wei. 2014. "Zero kinetic energy photoelectron spectroscopy of triphenylene". United States. https://doi.org/10.1063/1.4884905.
@article{osti_22311292,
title = {Zero kinetic energy photoelectron spectroscopy of triphenylene},
author = {Harthcock, Colin and Zhang, Jie and Kong, Wei},
abstractNote = {We report vibrational information of both the first electronically excited state and the ground cationic state of jet-cooled triphenylene via the techniques of resonantly enhanced multiphoton ionization (REMPI) and zero kinetic energy (ZEKE) photoelectron spectroscopy. The first excited electronic state S{sub 1} of the neutral molecule is of A{sub 1}′ symmetry and is therefore electric dipole forbidden in the D{sub 3h} group. Consequently, there are no observable Franck-Condon allowed totally symmetric a{sub 1}′ vibrational bands in the REMPI spectrum. All observed vibrational transitions are due to Herzberg-Teller vibronic coupling to the E′ third electronically excited state S{sub 3}. The assignment of all vibrational bands as e′ symmetry is based on comparisons with calculations using the time dependent density functional theory and spectroscopic simulations. When an electron is eliminated, the molecular frame undergoes Jahn-Teller distortion, lowering the point group to C{sub 2v} and resulting in two nearly degenerate electronic states of A{sub 2} and B{sub 1} symmetry. Here we follow a crude treatment by assuming that all e′ vibrational modes resolve into b{sub 2} and a{sub 1} modes in the C{sub 2v} molecular frame. Some observed ZEKE transitions are tentatively assigned, and the adiabatic ionization threshold is determined to be 63 365 ± 7 cm{sup −1}. The observed ZEKE spectra contain a consistent pattern, with a cluster of transitions centered near the same vibrational level of the cation as that of the intermediate state, roughly consistent with the propensity rule. However, complete assignment of the detailed vibrational structure due to Jahn-Teller coupling requires much more extensive calculations, which will be performed in the future.},
doi = {10.1063/1.4884905},
url = {https://www.osti.gov/biblio/22311292}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 24,
volume = 140,
place = {United States},
year = {Sat Jun 28 00:00:00 EDT 2014},
month = {Sat Jun 28 00:00:00 EDT 2014}
}