High-Dimensional Atomistic Neural Network Potential to Study the Alignment-Resolved O2 Scattering from Highly Oriented Pyrolytic Graphite.

ALEJANDRO RIVERO SANTAMARı́A; MAXIMILIANO RAMOS; MAITE ALDUCIN; BUSNENGO, HERIBERTO FABIO; RICARDO DIEZ MUIÑO; JUARISTI, JOSEBA IÑAKI

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Año: 2021

1089-5639

A high dimensional and accurate atomistic neural network potential energy surface (ANN-PES) that describes the interaction between one O2 molecule and a highly oriented pyroliticgraphite (HOPG) surface has been constructed, using the open source package aenet. The vali-dation of the PES is performed by paying attention to static characteristics as well as by testingits performance in reproducing previous ab initio molecular dynamics simulation results. Sub-sequently, the ANN-PES is used to perform quasiclassical molecular dynamics calculations ofthe alignment dependent scattering of O2 from HOPG. Results are obtained for 200 meV O2molecules with different initial alignments impinging with a polar incidence angle respect tothe surface normal of 22.5◦ on a thermalized (110 and 300 K) graphite surface. The choice ofthese initial conditions in our simulations is made in order to perform comparisons to recentexperimental results on this system. Our results show that the scattering of O2 from the HOPGsurface is a rather direct process, that the angular distributions are alignment dependent, andthat the final translational energy of end-on molecules is around 20% lower than that of side-on molecules. Upon collision with the surface, the molecules initially aligned perpendicular tothe surface become highly rotationally excited, whereas a very small change in the rotationalstate of the scattered molecules is observed for the initial parallel alignments. The latter con-firms the energy transfer dependence on the stereodynamics for the present system. The resultsof our simulations are in overall agreement with the experimental observations regarding theangular distributions shape and the alignment dependence of the in-plane reflected molecules.