Potential Energy Surface for Interactions Between H2 and Si: Ab Initio Calculations and Analytic Fits

An accurate three-dimensional potential energy surface (PES) for the interaction of rigid H-2 with Si is developed using the single and double excitation coupled cluster theory with noniterative treatment of triple excitations [CCSD (T)]. Mixed basis sets, aug-cc-pCVTZ for the Si atom and aug-cc-pVTZ for the H atom with midbond functions are used. We first fit the calculated single point energies to an analytic two-dimensional potential model at a fixed r (H-H) = 2.19a (0) value. The computations involve 198 ab initio points on the PES. The characteristics of the fitted PES are compared with those of previous surfaces. Our theoretical results in this work with an average absolute error of 0.3425 % and a maximum error less than 4.0072 % compared with the ab initio values calculated.