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

New reduced three-dimensional (3D) diabatic potential energy surfaces (PESs) involving the 1ππ, 1ππ*, and 1πσ* states for the nonadiabatic photodissociation C6H5SH(S0) + hv → C6H5SH(1ππ*/1πσ*) → H + C6H5S•(A/X) were constructed at a high computational level, namely explicitly 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 S0 state and the excitation energies of the excited S1 and S2 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 S0 and S1 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...