TY - JOUR
T1 - Embedded-cluster model for the effect of phonons on hydrogen surface diffusion on copper
AU - Lauderdale, Jack G.
AU - Truhlar, Donald G.
PY - 1986
Y1 - 1986
N2 - We treat surface diffusion of H on a (100) plane of copper by a model involving 21 degrees of freedom, three for the H and three each for six surface atoms. The six movable surface atoms are embedded on the surface of a bulk crystal. The interaction potential consists of pairwise H-Cu and Cu-Cu interactions, and the dynamics are treated by variational transition state theory with a small-curvature-approximation semiclassical adiabatic ground-state transmission coefficient. The classical barrier height for surface diffusion on the assumed potential energy surface is 11.7 kcal/mol, and we find an Arrhenius activation energy that increases from about 6 kcal/mol, below 160 K, to about 11 kcal/mol, above 400 K. The rate is dominated by tunneling at and below about 200 K. As compared to a treatment with a rigid surface the rate is increased by factors of 16, 3.1, 2.4, 1.6, and 1.3 at 110, 160, 200, 400, and 1000 K, respectively.
AB - We treat surface diffusion of H on a (100) plane of copper by a model involving 21 degrees of freedom, three for the H and three each for six surface atoms. The six movable surface atoms are embedded on the surface of a bulk crystal. The interaction potential consists of pairwise H-Cu and Cu-Cu interactions, and the dynamics are treated by variational transition state theory with a small-curvature-approximation semiclassical adiabatic ground-state transmission coefficient. The classical barrier height for surface diffusion on the assumed potential energy surface is 11.7 kcal/mol, and we find an Arrhenius activation energy that increases from about 6 kcal/mol, below 160 K, to about 11 kcal/mol, above 400 K. The rate is dominated by tunneling at and below about 200 K. As compared to a treatment with a rigid surface the rate is increased by factors of 16, 3.1, 2.4, 1.6, and 1.3 at 110, 160, 200, 400, and 1000 K, respectively.
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U2 - 10.1063/1.450431
DO - 10.1063/1.450431
M3 - Article
AN - SCOPUS:0001744163
SN - 0021-9606
VL - 84
SP - 1843
EP - 1849
JO - The Journal of chemical physics
JF - The Journal of chemical physics
IS - 3
ER -