Density functional theory investigation of the photodissociation channels of acetophenone

The photodissociations of acetophenone (C6H5COCH3) have been investigated by density functional theory (DFT) approach. The experimentally observed three photodissociation channels were clarified from the theoretical calculations on the related reactants, transition states (TSs), and products. Two of the three channels, C6H5COCH3 → C6H5CO + CH3 and C6H5COCH3 → C6H5 + CH3CO, were assigned to Norrish I reactions on the potential energy surfaces (PESs) of the lowest triplet state (T1). And, the first one is more favorable for lower barrier. The subsequent decompositions, C6H5CO → C6H5 + CO and CH3CO → CH3 + CO, were also studied by the similar calculations as above. The third photodissociation channel, C6H5COCH3 → C6H5CH3 + CO, has been documented on the PESs of the ground state (S0). The third one played a minor role in the photodissociations of C6H5COCH3 for much higher barrier than the first two.