The Full Dimensional And Global Potential Energy Surface Study Of CH₂⁺ System

The elements C,S and N are widely present in nature.Molecules composed of C and S play an important role in many molecular reactions,such as C,S combustion and atmospheric periodic pollution.In recent years,NS and CH₂⁺have become topic in the atomic and molecular physics investigations,and have inspired the interest of many scientists.Therefore,this paper mainly uses the extrapolation method to fit accurate NS potential energy curve and the CH₂⁺full dimensional and global potential energy surface.For NS system,the ab initio energy points are computed using full valence complete active space self-consistent field and multireference configuration interaction method with a basis set of aug-cc-pVXZ?X=T,Q,5 and 6?to the complete basis set limit.Then the extended Hartree-Fock approximate correlation energy model is employed to obtain the analytical potential energy functions of NS.Based on the analytical potential energy functions,the spectroscopic parameters such as the equilibrium nuclear distance and dissociation energy of the NS molecule were calculated.Comparing the existing theoretical and experimental data,it is found that the calculation results of CBS?Q,5?have a high accuracy.Finally,by using the radial Schr?dinger equation to solve the nuclear motion numerically,the complete vibrational states of NS molecules at J=0 is obtained for the first time:vibrational levels,classical turning points,inertial rotation constant and centrifugal distortion constants,and to predict the vibrational energy spectrum.For CH₂⁺system,the ab initio energies from MRCI?Q?based on the FVCAS reference wave function with the aug-cc-pVXZ?X=Q and 5?to the complete basis set limit using USTE?Q,5?method.The Aguado Paniagua function and three-body distributed polynomial method were used to fit CH⁺?H₂ and CH₂⁺,respectively.Total3255 energy points were calculated,the new function is completely analyzed.The contour maps of different geometries are plotted,and several stationary points of the potential energy surface are discussed,which are consistent with the corresponding experimental values and theoretical values.In order to verify the accurate of the new potential energy surface,we calculated the dynamics of H?²S?+CH⁺?X¹?⁺??C⁺?²P?+H₂?X¹?_g⁺?using quasi-classical trajectory method,the rate constants,differential cross section and the integral reaction cross section of the reaction were studied.Compared with the related data in other literature,we found that our potential energy surface can be used for any type of dynamic study.