Eur. Phys. J. D (2015) 69: 22
https://doi.org/10.1140/epjd/e2014-50445-3

Regular Article

Accurate adiabatic potential energy surface for 1²A′ state of FH₂ based on ab initio data extrapolated to the complete basis set limit^*

¹ Department of Physics, Liaoning University, Shenyang 110036, P.R. China
² State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
³ College of Physics and Electronics, Shandong Normal University, Jinan 250014, P.R. China
⁴ Departamento de Quimica and Centro de Quimica Universidade de Coimbra, 3004-535 Coimbra, Portugal

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

Received: 12 June 2014
Published online: 16 January 2015

Abstract

An accurate single-sheeted double many-body expansion potential energy surface is reported for the title system. It is obtained by using the aug-cc-pVTZ and aug-cc-pVQZ basis sets with extrapolation of the electron correlation energy to the complete basis set limit, plus extrapolation to the complete basis set limit of the complete-active-space self-consistent field energy. The collinear and bending barrier heights of the new global potential energy surface is 2.301 and 1.768 kcal mol^-1, in very good agreement with the values of 2.222 and 1.770 kcal mol^-1 from the current best potential energy surface. In particular, the new potential energy surface describes well the important van der Waals interactions which is very useful for investigating the dynamics of the title system. Thus, the new potential energy surface can both be recommended for dynamics studies of the F + H₂ reaction and as building block for constructing the potential energy surfaces of larger fluorine/hydrogen containing systems. Based on the new potential energy surface, a preliminary theoretical study of the reaction F(²P) + H₂ (X¹ Σ_g⁺) → FH(X¹Σ⁺) + H(²S) has been carried out with the methods of quasi-classical trajectory and quantum mechanical. The results have shown that the new PES is suitable for any kind of dynamics studies.