Chemically Accurate ab Initio Potential Energy Surfaces for the Lowest ^3A' and ^3A' ' Electronically Adiabatic States of O(^3P) + H_2

The electronic energies of the lowest ^3A' and ^3A'' states of the O(^3P) + H_2 system were calculated for 951 geometries using MOLPRO. The calculations were fitted by a rotating Morse spline method and independently by a generalized London−Eyring−Polanyi−Sato (LEPS) double-polynomial method. A higher accuracy calculation for 112 of these geometries was also performed for both ^3A' and ^3A'' to obtain correction potential energy surfaces (PESs) used to raise the accuracy of the original surfaces to about 0.3 kcal/mol. The resulting fitted PESs are presented and compared to each other and to a previous empirical LEPS surface.