A quantum-mechanical analysis of trans-acrolein vibrational spectra in the ground S0 and excited T1 and S1 electronic states

Abstract

The optimization of geometrical parameters and calculation of the force fields of trans-acrolein (CH2CHCHO) in the ground S0 and lowest excited triplet (T1) and singlet (S1) electronic states are performed at the CASPT2/def2-TZVPP theoretical level. Co-assignments of the vibrational frequencies calculated from the corresponding force fields are validated by calculations of the analogs of the Duschinsky matrix for the pairs of the (S0, T1) and (S0, S1) electronic states. The results obtained by comparing the vibrational frequencies calculated from the scaled force fields with the experimental vibrational frequencies made it possible to corroborate some details of the molecular structure in these electronic states.