Dynamics Investigations Of Several Polyatomic Reactions On Full Dimensional Potential Energy Surfaces

Chemical reaction is key to chemistry.The field of reaction dynamics aims to gain a microscopic understanding of chemical transformations by investigating quantum state resolved reactivity in the gas phase.Theoretically,it is important to construct high-precision potential energy surface?PES?for studying chemical reaction dynamics.In this work,systematic dynamical studies have been carried out for three reaction systems with their potential energy surfaces developed by the permutation invariant polynomial-neural network?PIP-NN?approach.For the H+H₂S system,33435 data points are sampled including both abstraction and exchange channels,and calculated at the level of explicitly correlated unrestricted coupled cluster method with singles,doubles,and perturbative triples excitations with theaugmentedcorrelation-consistentpolarizedtriplezetabasisset?UCCSD?T?-F12a/aug-cc-pVTZ?.The data set is fit with three different vectors as the input,four order?PES-I?,three order?PES-II?and nine non-redundant PIPs?PES-III?.After comparing and analysis of the three PESs,it is found that the PES-II has the smallest number of fitting parameters and the smallest fitting errors.Integral cross sections?ICSs?,differential cross sections?DCSs?and rovibrational state distributions are analyzed using the quasi-classical trajectory?QCT?approach,the difference of the ICS on three PES is negligible.Stationary points and rate coefficients,calculated using the software polyrate,agree well with experiment.For F+HCl?HF+Cl system,6509 data points are sampled to construst the ground electronic state PESs with and without spin-orbit correction.The rate coefficients of F+HCl?HF+Cl and F+DCl?DF+Cl are calculated by the ring polymer molecular dynamics?RPMD?approach.It is found that the theoretical rate coefficients in good agreement with the experimental results.The ICS and rate coefficients of the two reactions are also calculated by the quantum molecular reaction dynamics approach.For HO+CO?H+CO₂ system,we reconstruct a full-dimensional PES,which is the most accurate to date.With this PES,the reaction dynamics is computed using QCT.Specifically,the ICS and DCS are calculated at the collisional energies of 7.0,11.5,13.0,13.9,14.5,17.0 and 22.0 kcal/mol,starting from the ro-vibrational ground states of the reactants of H¹⁸O+CO?H+¹⁸OCO.The rate coefficients are also calculated by RPMD.The results are in good agreement with experiment.