Torsions, low-frequency vibrations, and vibration-torsion ("vibtor") levels in the m-chlorotoluene cation

David J Kemp; Lewis G Warner; Timothy G Wright

doi:10.1063/1.5142992

Torsions, low-frequency vibrations, and vibration-torsion ("vibtor") levels in the m-chlorotoluene cation

J Chem Phys. 2020 Feb 14;152(6):064303. doi: 10.1063/1.5142992.

Authors

David J Kemp¹, Lewis G Warner¹, Timothy G Wright¹

Affiliation

¹ School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.

PMID: 32061214
DOI: 10.1063/1.5142992

Abstract

Zero-electron-kinetic-energy (ZEKE) spectra are presented for m-chlorotoluene (mClT), employing different low-lying torsional and vibration-torsional ("vibtor") levels of the S₁ state as intermediates. The adiabatic ionization energy is determined to be 71 319 cm^-1 ± 5 cm^-1 (8.8424 ± 0.0006 eV). It is found that the activity in the ZEKE spectra varies greatly for different levels and is consistent with the assignments of the S₁ levels of m-fluorotoluene (mFT) deduced in the recent fluorescence study of Stewart et al. [J. Chem. Phys. 150, 174303 (2019)] and the ZEKE study from Kemp et al. [J. Chem. Phys. 151, 084311 (2019)]. As with mFT, the intensities in the ZEKE spectra of mClT are consistent with a phase change in the torsional potential upon ionization, allowing a large number of torsions and vibtor levels to be observed for the cation. Vibration-induced modifications of the torsional potential are discussed. Calculated vibrational wavenumbers for the S₀, S₁, and D₀ ⁺ states are also presented.