A multi-sheeted three-dimensional potential-energy surface for the H-atom photodissociation of phenol

Extending the previous work of Lan et al. [J. Chem. Phys., 122, 224315 (2005)], a multi-state potential model for the H atom photodissociation is presented. All three "disappearing coordinates" of the departing H atom have been considered. Ab initio CASSCF computations have been carried out for the linear COH geometry of C_2v symmetry, and for several COH angles with the OH group in the ring plane and also perpendicular to the ring plane. By keeping the C₆H₅O fragment frozen in a C _2v-constrained geometry throughout, we have been able to apply symmetry-based simplifications in the constructions of a diabatic model. This model is able to capture the overall trends of twelve adiabats at both torsional limits for a wide range of COH bend angles.