A new analytical potential energy surface for the singlet state of He _2H ~+

摘要

The analytic potential energy surface (APES) for the exchange reaction of HeH ~+ (X ~(1+)) He at the lowest singlet state 1 ~1A ~+ has been built. The APES is expressed as Aguado-Paniagua function based on the many-body expansion. Using the adaptive non-linear least-squares algorithm, the APES is fitted from 15 682 ab initio energy points calculated with the multireference configuration interaction calculation with a large d-aug-cc-pV5Z basis set. To testify the new APES, we calculate the integral cross sections for He H ~+He (v =0, 1, 2, j 0) → HeH He by means of quasi-classical trajectory and compare them with the previous result in literature.