Constructing accurate potential energy surfaces for a diatomic molecule interacting with a solid surface: H2/Pt(111) and H2/Cu(100)

OLSEN, R.A.; BUSNENGO, H.F.; SALIN, A.; SOMERS, M.F.; KROES, G.J.; BAERENDS, E.J.

JOURNAL OF CHEMICAL PHYSICS

Año: 2002 vol. 116 p. 3841 - 3855

0021-9606

By applying a corrugation-reducing procedure we have interpolated the six-dimensional 6D potential energy surfaces for the H2 /Pt(111) and H2 /Cu(100) systems from data obtained by density functional theory DFT calculations. We have compared interpolated values with a large number of DFT results not used in the basis for the interpolation and we have obtained an average error below 20 meV and a maximum error of about 30 meV in the regions important for dissociative adsorption. Near the surface the corrugation-reducing procedure gives excellent results using only data from high-symmetry sites. However, we show that to reach the above mentioned accuracy level far from the surface, it is necessary to include information from at least one low-symmetry site. Care has been taken to demonstrate the quality of the interpolation along all degrees of freedom in different regions of the configuration space. The strengths of the method are shown together with theaspects requiring careful handling. A comparison with a direct interpolation method is also made.