Diffusion of Hydrogen on Ni(111) over a Wide Range of Temperature: Exploring Quantum Diffusion on Metals

作者：Gang Cao, E. Nabighian, X. D. Zhu · 发表于：Physical Review Letters · 年份：1997 · DOI：10.1103/physrevlett.79.3696 · 被引用次数：105 · 研究领域：Advanced Chemical Physics Studies、Quantum, superfluid, helium dynamics、nanoparticles nucleation surface interactions

We measured the temperature and azimuthal dependence of the diffusion rates of hydrogen ( ${}^{1}\mathrm{H}$) and deuterium ( ${}^{2}\mathrm{H}$) 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.