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.