Calculation of absorption spectrum of the g u A B 1 1 1 1 electronic transition of Calculation of absorption spectrum of the g u A B 1 1 1 1 electronic transition of

The general expressions we recently derived for calculating of the vibronic structure in electronic absorptionspectrum of a large polyatomic molecule based on time-domain approach are applied to simulate the vibronicstructure in the dipole-allowed g u A B 1 1 1 1 electronic transition of trans-1,3,5-hexatriene molecule. Thecalculated results indicated that spectral profiles are primarily described by the Franck-Condon progression offour totally symmetric modes, 5  , 10  , 11  and 13  , among which the 5  (CC double bond stretch) and 10  (CCsingle bond stretch) are the longest progression-forming modes, while the modes 11  and 13  have much lessactivities. The spectra also show combination bands (as 1 1 5 11 , 1 1 5 10 , etc.) produced by the g a modes.

Keywords:

molecular absorption , time-domain approach , linear polyene