Surface diffusion of deuterium and hydrogen on Pt(111) has been investigated by laser-induced thermal desorption. As the initial surface coverage of deuterium is varied from 0.001 to 0.33, the diffusional activation energy falls from 12 to 7 kcal mol, and the pre-exponential factor falls from 3 × 104 to 0.5 cm2/s. Concentration profiles measured directly by a variable aperture technique confirm that at 234 K deuterium diffusion slows at low coverage. Hydrogen diffuses about twice as fast as deuterium.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry