Full Quantum dynamics study for H atom scattering from graphene

TL;DR

This paper advances quantum dynamics simulations of hydrogen atom scattering from graphene, incorporating full-dimensional models and plane wave approaches to better understand energy transfer and bond formation, revealing quantum effects and discrepancies with classical models.

Contribution

Refined quantum dynamics methods for H-graphene scattering, including plane wave initial states and full-dimensional simulations, improving realism and comparison with experiments.

Findings

Discrepancies between cMD and experimental results due to potential energy surface and quantum effects.

Quantum effects significantly influence energy transfer during H-graphene collisions.

Classical normal modes play a role in collision energy transfer processes.

Abstract

This study deals with the understanding of hydrogen atom scattering from graphene, a process critical for exploring C-H bond formation and energy transfer during the atom surface collision. In our previous work (J.Chem.Phys \textbf{159}, 194102, (2023)), starting from a cell with 24 carbon atoms treated periodically, we have achieved quantum dynamics (QD) simulations with a reduced-dimensional model (15D) and a simulation in full dimensionality (75D). In the former work, the H atom attacked the top of a single C atom, enabling a comparison of QD simulation results with classical molecular dynamics (cMD). Our approach required the use of sophisticated techniques such as Monte Carlo Canonical Polyadic Decomposition (MCCPD) and Multilayer Multi-Configuration Time-Dependent Hartree (ML-MCTDH), as well as a further development of quantum flux calculations. We could benchmark our calculations by comparison with cMD calculations. We have now refined our method to better mimic experimental conditions. Specifically, rather than sending the H atom to a specific position on the surface, we have employed a plane wave for the H atom in directions parallel to the surface. Key findings for these new simulations include the identification of discrepancies between classical molecular dynamics (cMD) simulations and experiments, which are attributed to both the potential energy surface (PES) and quantum effects. Additionally, the study sheds light on the role of classical collective normal modes during collisions, providing insights into energy transfer processes. The results validate the robustness of our simulation methodologies and highlight the importance of considering quantum mechanical effects in the study of hydrogen-graphene interactions.