Rotationally Inelastic Scattering Dynamics of NO from Ag(111): Influence of Interaction Potentials

Abstract

State-to-state molecular scattering from surfaces represents a sensitive probe of the molecule−surface interaction potential. For NO scattering from Ag(111), a benchmark system for studying gas−surface energy transfer, abundant experimental data have provided us a great testing ground to validate the accuracy of first-principles description of molecule−surface interactions. Here, we use an accurate neural network fitting method to construct two high-dimensional potential energy surfaces (PESs) based on density functional theory (DFT) single points using PBE and revPBE functionals, respectively, for describing the rotationally inelastic scattering of NO from Ag(111). Quasi-classical trajectory calculations based on the two PESs have been compared with a diversity of experimental data and the influence of scattering angle, initial molecular orientation, and incidence energy on the rotational state distribution is discussed. It is found in general that revPBE-based results agree better than PBE-based ones with the measured scattering angle and final rotational state distributions, capturing reasonably the rotational rainbow feature at a small incidence energy and the steric effect. But neither PES reproduces all experimental data quantitatively. The different performance of the two PESs can be attributed to their difference in the attractiveness, anisotropy, and corrugation in the entrance channel. Our results suggest the need of further improvement of the accuracy of DFT with commonly used density functionals toward a chemically accurate description of molecule−surface interactions.

Vibrational energy transfer in collisions of molecules with metal surfaces

“…This prompted several theoretical groups to construct more accurate adiabatic and diabatic PESs paying close attention to the choice of the DFT functional and using neural network methods to reduce the fitting error. Several theory groups produced a set of such potentials with impressive accuracy for NO at Au(111), 69,110–113 NO at Ag(111), 114 NO at LiF(001), 111 CO at Au(111), 73,113,115,116 H 2 at Ag(111), 106 and HCl at Au(111) 117–119 (see also the perspective paper 120 and review 121 ). For modelling of the collisional relaxation of highly vibrationally excited molecules, the energy landscape close to the dissociation barrier is very sensitive to the choice of the functional and strongly affects the predicted outcomes.…”

“…113 The Born–Oppenheimer molecular dynamics (BOMD) simulations performed on the new NN-PES revealed a surprisingly large contribution to relaxation from an adiabatic mechanism for NO and CO scattering, arising from the softening of the vibrational potential for high vibrational states. 113,114…”