Influence of substrate motion on the self-diffusion of hydrogen and its isotopes on the copper (100) surface
Work is presented that examines the effect of substrate motion on the surface self-diffusion of hydrogen and its isotopes on the Cu(100) surface. Lattice motion, represented as a sum of Lennard-Jones interactions, is found to increase the diffusion constant of hydrogen and its isotopes at all temperatures examined. The increase varies from 1.3 to 4.0 over the temperature range from 1000 to 110 K. The results agree with the recent calculations of Lauderdale and Truhlar above 150 K. The quantum contribution to the isotope effect is enhanced relative to the values for the frozen substrate. These conclusions are based on approximate path integral calculations in which quantum-mechanical effects are treated in a semiclassical manner using temperature-dependent effective potentials. The differences between the present results and those of Lauderdale and Truhlar are attributed to a breakdown of these semiclassical approximations at low temperatures. In the temperature range considered, commonly accepted harmonic corrections to the classical results afford slightly poorer agreement with Lauderdale and Truhlar than the present results.
- Research Organization:
- MST-3, Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 7164446
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 85:12
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER
SURFACE PROPERTIES
HYDROGEN
SELF-DIFFUSION
FEYNMAN PATH INTEGRAL
HIGH TEMPERATURE
LENNARD-JONES POTENTIAL
LOW TEMPERATURE
MEDIUM TEMPERATURE
QUANTUM MECHANICS
SUBSTRATES
DIFFUSION
ELEMENTS
INTEGRALS
MECHANICS
METALS
NONMETALS
POTENTIALS
TRANSITION ELEMENTS
656000* - Condensed Matter Physics