Automatic potential energy surface generation directly from ab initio calculations using Shepard interpolation: A test calculation for the H2+H system

Toshimasa Ishida, George C Schatz

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

A modified version of the Shepard interpolation scheme proposed recently by Collins et al. is used to determine a potential energy surface for the H2-H reaction. Our modifications are based on preliminary calculations in which the Liu-Siegbahn-Truhlar-Horowitz surface for H3 is used to study convergence of the Shepard procedure. Included in the modifications are changes to the form of the weight functions, the coordinate sets used in the zeroth-order surface, and the transformation of the Cartesian first and second derivatives to internal coordinates. The new ab initio potential energy surface is based on calculations using the basis set of Siegbahn and Liu and second order Møller-Plesset (MP2) perturbation calculations. We have not experienced convergence problems with the self-consistent-field iteration while "growing" the surface. Furthermore, a converged fit can be obtained using only 85 ab initio calculations. This demonstrates that the Shepard interpolation scheme is a powerful candidate for automatic determination of medium quality potential surfaces for dynamical calculations.

Original languageEnglish
Pages (from-to)3558-3568
Number of pages11
JournalJournal of Chemical Physics
Volume107
Issue number9
Publication statusPublished - Sep 1 1997

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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