Abstract
We measured the temperature and azimuthal dependence of the diffusion rates of hydrogen (1H) and deuterium (2H) on Ni(111) from 65 to 240 K where the diffusion rates vary by 8 orders of magnitude. The diffusion of hydrogen crosses over from an activated behavior above 110 K to another activated behavior below 110 K with a smaller activation energy. By ruling out the possibility of a step effect, we suggest that the crossover is from a classical overbarrier hopping to a quantum mechanical underbarrier tunneling.
Original language | English (US) |
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Pages (from-to) | 3696-3699 |
Number of pages | 4 |
Journal | Physical Review Letters |
Volume | 79 |
Issue number | 19 |
State | Published - Nov 10 1997 |
ASJC Scopus subject areas
- Physics and Astronomy(all)