Accurate Adiabatic and Diabatic Potential Energy Surfaces for the Reaction of He + H2

The accurate adiabatic and diabatic potential energy surfaces, which are for the two lowest states of He + H-2, are presented in this study. The Molpro 2012 software package is used, and the large basis sets (aug-cc-pV5Z) are selected. The high-level MCSCF/MRCI method is employed to calculate the adiabatic potential energy points of the title reaction system. The triatomic reaction system is described by Jacobi coordinates, and the adiabatic potential energy surfaces are fitted accurately using the B-spline method. The equilibrium structures and electronic energies for the H-2 are provided, and the corresponding different levels of vibrational energies of the ground state are deduced. To better express the diabatic process of the whole reaction, avoid crossing points being calculated and conical intersection also being optimized. Meanwhile, the diabatic potential energy surfaces of the reaction process are constructed. This study will be helpful for the analysis of histopathology and for the study in biological and medical mechanisms.

Automated summary

The accurate adiabatic and diabatic potential energy surfaces for the two lowest states of He + H-2 were calculated using the Molpro 2012 software package and large basis sets (aug-cc-pV5Z). The adiabatic potential energy surfaces were fitted accurately using the B-spline method, and the diabatic potential energy surfaces of the reaction process were constructed. The study provides insights into the adiabatic process of the reaction system and will be beneficial for histopathology analysis and the study of biological and medical mechanisms.