Classical and quantum diffusion of hydrogen atoms on Cu(1 1 1)

X. Wang, Y. Y. Fei, X. D. Zhu

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

We measured diffusion constants of hydrogen adatoms on Cu(1 1 1) using a combination of enabling optical techniques. We observed a steep crossover from a strongly thermal activated hopping (T > 130 K) to a weakly thermal activated 'hopping' (T < 130 K). The diffusion at high temperatures is characterized by a large barrier Ediff (1) = 450 meV and a large pre-exponential factor D0 (1) = 162 cm2 / s, indicating that it is dominated by the kinetics of crossing step edges. The weakly activated diffusion at low temperatures is characterized by a much smaller 'barrier' of Ediff (2) = 22 meV and a pre-exponential factor D0 (2) = 6.8 × 10- 14 cm2 / s, characteristic of a quantum under-barrier tunneling.

Original languageEnglish (US)
Pages (from-to)58-61
Number of pages4
JournalChemical Physics Letters
Volume481
Issue number1-3
DOIs
StatePublished - 2009

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Physics and Astronomy(all)

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