Symmetry forbidden vibronic spectra and internal conversion in benzene
Journal
Physical Chemistry Chemical Physics
Journal Volume
12
Journal Issue
45
Pages
14967-14976
Date Issued
2010
Author(s)
Abstract
The spectra of symmetry-forbidden transitions and internal conversion were investigated in the present work. Temperature dependence was taken into account for the spectra simulation. The vibronic coupling, essential in the two processes, was calculated based on the Herzberg-Teller theory within the Born-Oppenheimer approximation. The approach was employed for the symmetry-forbidden absorption/fluorescence, and internal conversion between 11A1g and 11B2u states in benzene. Vibrational frequencies, normal coordinates, electronic transition dipole moments, and non-adiabatic coupling matrix elements were obtained by ab initio quantum chemical methods. The main peaks, along with the weak peaks, were in good agreement with the observed ones. The rate constant of the 1 1A1g ??11B2u internal conversion was estimated within the order of 103 s-1. This could be regarded as the lower limit (about 4.8 ? 103 s -1) of the internal conversion. It is stressed that the distortion effect was taken into account both in the symmetry-forbidden absorption/fluorescence, and the rate constants of internal conversion in the present work. The distortion effects complicate the spectra and increase the rate constants of internal conversion. ? the Owner Societies 2010.
SDGs
Other Subjects
benzene; absorption; article; chemistry; quantum theory; spectrofluorometry; vibration; Absorption; Benzene; Quantum Theory; Spectrometry, Fluorescence; Vibration
Type
journal article