Eur. Phys. J. D (2014) 68: 3
https://doi.org/10.1140/epjd/e2013-40440-7

Regular Article

Accurate ab initio-based DMBE potential energy surface for HLi₂(X  ²A′) via scaling of the external correlation

¹ College of Physics and Electronics, Shandong Normal University, Jinan 250014, P.R. China
² Department of Physics, Liaoning University, Shenyang 110036, P.R. China

^a e-mail: yzsong@sdnu.edu.cn
^b e-mail: qtmeng@sdnu.edu.cn

Received: 23 July 2013
Received in final form: 22 October 2013
Published online: 22 January 2014

Abstract

A globally accurate potential energy surface is reported for the electronic ground-state HLi₂ by fitting ab initio energies to double many-body expansion formalism. The total 3726 ab initio energies used to map the HLi₂ potential energy surface are calculated using the multi-reference configuration interaction method, with their dynamical correlation being semiempirically corrected by the double many-body expansion-scaled external correlation method. The current potential energy surface generates an excellent fit of the ab initio energies, showing a small root-mean squared derivation of 0.636   kcal   mol^-1. The topographical features of the HLi₂ potential energy surface are examined in detail, which concludes that the H + Li₂(X   ¹Σ_g) → Li + LiH(X   ¹Σ) reaction is essentially barrierless and the exothermicity is calculated to be 33.668   kcal   mol^-1, thus corroborates the available experimental and theoretical results.