The Construction Of A New Potential Energy Surface For The LiH₂⁺ System And Dynamic Studies Of The LiH⁺（X²Σ⁺） + H（²S）→Li⁺（¹S） + H₂（X¹Σ_g

Molecular reaction dynamics is an important branch of chemical physics,which is a subject of studying the micro-reaction mechanism and the rate of chemical reaction.As the basis and premise of the reaction dynamics,the quality of the potential energy surface directly determines the accuracy of the dynamics results.In this work,a new potential energy surface（PES）of the LiH₂⁺ system is built by using the neural network method,and then using the time-dependent quantum wave packet（TDWP）and quasi classical trajectory calculations（QCT）study the reaction dynamics based on the new PES.The specific work is as follows:Based on a large number of high-precision ab initio energy points,the new potential energy surface of the LiH₂⁺ system was fitted by neural network.The energy points are calculated using the WCVQZ and AVQZ basis sets with the MRCI method.The spectral constants such as the equilibrium bond length and dissociation energy,which is calculated by the new potential surface are in good agreement with the experiment.For the whole reaction process,the quasi-classical trajectory method’s results are in good agreement with the time-dependent wave packet methods except for the low collision energy region.It’s because of the quantum effect is obvious.The integrated cross section value is high in the low collision energy region,and the ICS is getting smaller with the energy increasing.At the exit of the reaction channel,there is a very shallow Van der Waals well and it will produce a short-lived intermediate complex during the reaction,which resulting in asymmetric scattering of the product molecules.The results of the differential reaction cross section show that in the low collision energy region there are two kinds of scattering before and after the reaction,and the product tends to forward scattering as the collision energy increases.The results of the differential reaction cross section show that there are both forward and backward two kinds scattering in the low collision energy region.And the product tends to forward scattering as the collision energy increases.