Representation of the 6D potential energy surface for a diatomic molecule near a solid surface

An efficient method is proposed to construct the six-dimensional Potential Energy Surface (PES) for diatomic molecule-surface interactions from low di mensional cuts obtained in ab initio calculations. The efficiency of our me thod results from a corrugation-reducing procedure based on the observation that most of the corrugation in a molecule-surface PES is already embedded in the atom-surface interactions. Hence, substraction of the latter leads to a much smoother function which makes accurate interpolations possible. T he proposed method is a general one and can be implemented in a systematic way for any system. Its efficiency is illustrated for the case of H-2/Pd(11 1) by using recent ab initio data. We report also the results of very strin gent checks against ab initio calculations not used in the interpolation. T hese checks show the high accuracy of our method. (C) 2000 American Institu te of Physics. [S0021-9606(00)00717-0].