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

• Published in: The European physical journal. D, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2014, Vol.68 (1), Article 3
• Main Authors: Song, Yu-Zhi, Li, Yong-Qing, Gao, Shou-Bao, Meng, Qing-Tian
• Format: Article
• Language: English
• Subjects: Ab initio calculations; Applications of Nonlinear Dynamics and Chaos Theory; Atomic; Atomic and molecular clusters; Atomic and molecular physics; Calculations and mathematical techniques in atomic and molecular physics (excluding electron correlation calculations); Electronic and magnetic properties of clusters; Electronic structure of atoms, molecules and their ions: theory; Exact sciences and technology; Molecular; Optical and Plasma Physics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Information Technology; Quantum Physics; Regular Article; Spectroscopy/Spectrometry; Spintronics; Studies of special atoms, molecules and their ions; clusters
• ISSN: 1434-6060; 1434-6079
• DOI: 10.1140/epjd/e2013-40440-7

A globally accurate potential energy surface is reported for the electronic ground-state HLi 2 by fitting ab initio energies to double many-body expansion formalism. The total 3726 ab initio energies used to map the HLi 2 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 HLi 2 potential energy surface are examined in detail, which concludes that the H + Li 2 ( X   1 Σ g ) → Li + LiH( X   1 Σ ) reaction is essentially barrierless and the exothermicity is calculated to be 33.668   kcal   mol -1 , thus corroborates the available experimental and theoretical results.