CEPA calculations of Potential Energy Surface for open shell systems IV. Photodissociation of H2O in the A B1 State.

A three-dimensional potential energy surface for the photodissociation of H2O in its lowest excited singlet state A1B1 in C2v or A1A? in C3 symmetry, respectively, has been calculated with quantum-chemical ab initio methods including electron correlation. The main features of the surface are discussed and qualitative explanations are given for the experimentally observed vibrational and rotational excitations of the product OH(2?) radicals. The surface will be used in subsequent investigations of the dynamics of the H2O photodissociation process.