Ring Polymer Molecular Dynamics Rates for Hydrogen Recombinative Desorption on Pt(111)

The ring polymer molecular dynamics (RPMD) rate theory, which is capable of handling nuclear quantum effects such as zero-point energy and tunneling, is applied to the recombinative desorption (RD) of adsorbed hydrogen atoms on a Pt(111) surface, a fundamental surface reaction crucial in heterogeneous catalysis. Recent experiments have provided highly accurate measurements of hydrogen RD rates, offering rare benchmarks for theoretical predictions. The RPMD rate coefficients of H2 RD on an experimentally calibrated first-principles potential energy surface closely match the experimental data within a factor of 2 at several temperatures. Importantly, our results reveal that the dominant nuclear quantum effect in this prototypic system is the reactant zero-point energy, rather than tunneling.