Accurate Reproducing Kernel-Based Potential Energy Surfaces for the Triplet Ground States of N$_2$O and Dynamics for the N+NO$\leftrightarrow$O+N$_2$ and N$_2$+O$\rightarrow$2N+O Reactions

Abstract: Accurate potential energy surfaces (PESs) have been determined for the $^3$A$'$ and $^3$A$''$ states of N$_2$O using electronic structure calculations at the multireference configuration interaction level with Davidson correction (MRCI+Q) and the augmented Dunning-type correlation consistent polarize triple zeta (aug-cc-pVTZ) basis set. More than 20000 MRCI+Q/aug-cc-pVTZ energies are represented using a reproducing kernel Hilbert space (RKHS) interpolation scheme. The RKHS PESs successfully describe all reactant channels with high accuracy. The analytical PESs are characterized by computing the minima and transition states on it. Quasiclassical dynamics simulations are then used to determine thermal and vibrational relaxation rates for the N+NO and O+N$_2$ collisions. The agreement between results obtained from the simulations and from available experiments is favourable for both types of observables, which provides a test for the accuracy of the PESs. The PESs can be used to calculate more detailed state-to-state observables relevant for applications to hypersonic reentry.