Ab initio studies of excited electronic state S 2 of pyrazine and Franck-Condon simulation of its absorption spectrum

Rongxing He, Chao Yuan Zhu*, Chih Hao Chin, Sheng Hsien Lin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The equilibrium geometry and 24 vibrational-normal-mode frequencies of the excited state S 2 ( 1 B 2u ) of pyrazine are calculated and characterized using the complete active space self-consistent field method in the adiabatic representation. The displaced harmonic oscillator approximation is used to simulate the absorption spectrum of the S 2 ( 1 B 2u ) state along with the Franck-Condon approximation. It is found that the totally symmetric mode ν 1 plays the most important role and this exactly agrees with the experimental observations. The simulated absorption spectrum agrees well with those experimentally observed. This indicates that the present S 2 ( 1 B 2u ) state calculated in the adiabatic representation effectively includes contribution from the diabatic vibronic coupling through the conical intersection.

Original languageEnglish
Pages (from-to)19-24
Number of pages6
JournalChemical Physics Letters
Volume476
Issue number1-3
DOIs
StatePublished - 7 Jul 2009

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