Using n-mode potentials for reactive scattering: Application to the 6D H2 + Pt(1 1 1) problem

The accuracy of n-mode representations of potential energy surfaces (PESs) is investigated, for a reaction involving six degrees of freedom. Probabilities computed with the time-dependent wave packet (TDWP) method for reaction of (v = 0,1; j = 0) H2 on Pt(1 1 1) employing a 5-mode (4-mode) PES show quantitative (semi-quantitative) agreement with results for the full PES. The ratio of the v = 1 and v = 0 reaction probabilities obtained with the 5-mode PES is in quantitative agreement with full PES results for most of the energy range considered. The results suggest that n-mode representations can be employed successfully to study reactions of polyatomic molecules with surfaces.