Quantum and classical molecular dynamics for H atom scattering from graphene.

Area of Science:

• Computational Chemistry
• Surface Science
• Quantum Mechanics

Background:

• Accurate simulation of atom-surface interactions is crucial for understanding surface chemistry and catalysis.
• Classical molecular dynamics (cMD) and quantum dynamics (QD) offer different approaches to modeling these interactions.
• The development of accurate potential energy surfaces (PES) is essential for reliable simulations.

Purpose of the Study:

• To systematically compare classical molecular dynamics (cMD) and quantum dynamics (QD) simulations for hydrogen atom scattering on graphene.
• To investigate the influence of incident kinetic energy on the differences between cMD and QD.
• To benchmark quantum dynamics simulations against classical methods for a realistic, large-scale system.

Main Methods:

• Utilized an experimentally validated, full-dimensional neural network potential energy surface (PES) for H atom interaction with a 24-atom graphene cell.
• Applied Monte Carlo canonical polyadic decomposition to transform the PES into a sum-of-products form for QD simulations.
• Employed the multi-layer multi-configuration time-dependent Hartree (ML-MCTDH) method for simulating quantum scattering of H or D atoms.

Main Results:

• Little difference observed between cMD and QD simulations when the incident H atom energy was 1.96 eV.
• A significant difference in sticking probability was found at an incident H atom energy of 0.96 eV, indicating quantum effects.
• New projectors were implemented in the Heidelberg ML-MCTDH package for calculating atom scattering energy transfer distributions.

Conclusions:

• Quantum dynamics simulations reveal significant deviations from classical simulations at lower incident energies for H atom scattering on graphene.
• The study provides the first benchmark comparison of quantum versus classical simulations for a large system with a realistic PES.
• The findings underscore the importance of quantum mechanical treatments for accurately describing atom-surface dynamics, particularly concerning sticking probabilities.