Time-dependent Wave Packet Dynamical Calculations Of C⁺+H₂ And Potential Energy Surface Construction Of S+OH

Molecular reaction kinetics is a discipline that studies chemical reactions,it is mainly focused on reactions at the microscopic level.By investigating the kinetics of molecular reactions,we can not only obtain the structure,properties and effects of various instantaneous products of the reaction molecules in the reaction process,but also simply explain and indicate the inherent laws of chemical reactions from the point of view state-state chemical reaction kinetics.In recent years,the exploration of chemical reaction kinetics has become more deeply both in theory and experiment,and it can even involve the molecular level.In theory,the time-dependent wave packet method among many methods,which is one of the methods for calculating quantum dynamics,can provide some images for the study of dynamics.These images are relatively simple and clear,but the obtained kinetic information is both intuitive and accurate.In this paper,we use the time-dependent wave packet method to calculate and obtain the kinetic information for C⁺+H₂（HD,D₂）→CH⁺（CD⁺）+H（D）reactions in the collision range of 0.3-1.3 eV,which is calculated on the ground potential energy surface（PES）ofCH₂^（10）（1²A’）.At the same time,we calculated the reaction probabilities,reaction cross sections and the reaction rate constants for these reactions under Centrifugal sudden（CS）and Coriolis coupling（CC）conditions.The calculated results of this paper are the reaction probabilities and reaction cross sections showed the obvious oscillation phenomenon owing to the complex-forming mechanism with a deep well（when j=0）.When the reactants are excited by rotation（j=0,1,2）,the reaction probability of the reaction is approximately the same.And the values of CC probability is greater than the of CS probability.For low J values（J<10）,the differences between the CS and CC probabilities are small.However,as J becomes larger,remarkable differences appear.The integral reaction cross section of the C⁺+H₂（HD,D₂）→CH⁺（CD⁺）+H（D）reaction increases monotonically with increasing collision energy.The reaction cross section between CC and CS integral cross section is almost the same at the collision range of 0.3-0.45 eV.The CC integral cross section is larger than the CS integral cross section with the increase of collision energy.The reaction of C⁺+HD→CH⁺（CD⁺）+D（H）has two reaction channels,CH⁺+D channel and CD⁺+H channel.For the CD⁺+H channel,the calculated result is close to the experimental results in the collision energy range0.47-0.75 eV.However,for the CH⁺+D channel,the calculated result is close to the experimental results in the high collision energy range 0.9-1.3 eV.The calculated the reaction threshold（0.435 eV）and thermochemical endotherm（0.43 eV）are still very close for the reaction of C⁺+D₂→CD⁺+D.And we calculated the reaction cross-section of the reaction are in good agreement with the experimental fitted well in collision range of0.55-0.75 eV and in good agreement with the phase space theory（PST）in collision range of 0.5-0.9 eV.In the temperature range of 200-2500 K,For the C⁺+H₂→CH⁺+H reaction,the Coriolis coupling（CC）effect has an effect on the thermal rate constant of the reaction.As the temperature increases,the influence of the Coriolis coupling effect increases,and the calculated value of CS thermal rate constant is in good agreement with the experimental values.There is no significant oscillation due to the averaging of collision energy of the rate constant.For the reactions of C⁺+HD→CH⁺（CD⁺）+D（H）and C⁺+D₂→CD⁺+D,the experimental values are larger than our calculated CS thermal rate constant.For the construction of the potential energy surface of the system S+OH,we use the multiple reference configuration interaction method（MRCI）to do ab initio.The S-atoms were tested on the basis of the aug-cc-PV（5+d）Z group,the O and H atoms were on the basis of the aug-cc-PV5Z group,and the activation space was on 10 A’orbits and 3 A’’orbits.We chose 20576 points.