An accurate prediction of adiabatic excitation energies to the low-lying electronic states for acetophenone and the related carbonyl compounds

The complete active space self-consistent field method has been used to optimize planar minimum energy structures of the lowest five electronic states for benzaldehyde, acetophenone and the related aromatic ketones. The adiabatic excitation energies from the ground state to the (3)npi*(T-1), (1)npi*(S-1), (3)pipi*(T-2) and (1)pipi*(S-2) states were determined, which are in a good agreement with the experimental band origins where available. The present calculations predict that the adiabatic excitation energy to each excited electronic state investigated is nearly a constant for a wide range of aromatic carbonyl compounds. (C) 2003 Elsevier B.V. All rights reserved.