Three-Dimensional Diabatic Potential Energy Surfaces for the Photodissociation of Thiophenol

New reduced three-dimensional (3D) diabatic potential energy surfaces (PESs) involving the (1)pi pi, (1)pi pi* and (1)pi sigma* states for the nonadiabatic photodissociation C6H5SH(S-0) + hv -> C6H5SH((1)pi pi*/(1)pi sigma*) -> H + C6H5S center dot(A/X) were constructed at a high computational level, namely explicidy correlated multireference configuration interaction (MRCI-F12) method with the cc-pVTZ-F12 basis. The diabatization of the PESs was achieved by a simple, efficient, and reliable regularized diabatization method [Koppel, H.; Gronki, J.; Mahapatra, S. J. Chem. Phys. 2001, 115, 2377-2388]. The dissociation energy of the S-0 state and the excitation energies of the excited S-1 and S-2 states were found to be in reasonably good agreement with the experimental values. The vibronic energy levels of the thiophenol (PhSH) and deuterated thiophenol (PhSD) for S-0 and S-1 states were calculated using a three-dimensional model, and they are in reasonably good agreement with the available experimental results, which validate the high accuracy of the adiabatic PESs and the reasonability of the diabatic couplings.