Structure and dynamics of acrolein in 1,3(π,π*) excited electronic states: A quantum-chemical study

The geometrical structure, conformer energy differences, and conformational and vibrational dynamics of acrolein in 1,3(π,π*) electronic states were investigated using a number of single- and multi-reference quantum-chemical methods. Peculiarities of acrolein in the 1(π,π*) state were described with both conformers being significantly non-planar. A Valence Focal-Point Analysis of the conformer energy difference in the 3(π,π*) state was performed. The coupling of the internal rotation about CC and CC bonds with large amplitude molecular motions, such as non-planar distortions of carbonyl, methylene, and methyne fragments was also investigated. The corresponding two-dimensional PES sections were constructed.