Locating the rate-limiting step for the interaction of hydrogen withMg(0001)using density-functional theory calculations and rate theory

Tejs Vegge
2004 Physical Review B  
The dissociation of molecular hydrogen on a Mg͑0001͒ surface and the subsequent diffusion of atomic hydrogen into the magnesium substrate is investigated using Density Functional Theory (DFT) calculations and rate theory. The minimum energy path and corresponding transition states are located using the nudged elastic band method, and rates of the activated processes are calculated within the harmonic approximation to transition state rate theory, using both classical and quantum partition
more » ... tum partition functions based atomic vibrational frequencies calculated by DFT. The dissociation/recombination of H 2 is found to be rate-limiting for the ab-and desorption of hydrogen, respectively. Zero-point energy contributions are found to be substantial for the diffusion of atomic hydrogen, but classical rates are still found to be within an order of magnitude at room temperature.
doi:10.1103/physrevb.70.035412 fatcat:eingpkajvnaepdryh3qvgpcsza