Abstract
The trapping probabilities of argon, krypton, and xenon on Pd(1�1�1)
and Ni(1�1�1) have been investigated using supersonic molecular beam
techniques. The trapping probability of argon exhibits normal incident
energy in a similar fashion on both Pd(1�1�1) and Pt(1�1�1) because
the mass of argon is significantly less than the surface mass of
either Pd or Pt. In contrast, dynamic corrugation in the gas-surface
potential is observed for krypton trapping on Pt(1�1�1) and Pd(1�1�1),
resulting in a decreased angular dependence of the trapping probability
compared to argon. For xenon trapping on Pd significant lattice deformation
during the gas-surface collision appears to give rise to total energy
scaling. The trapping probability of xenon on Pd(1�1�1) remains high
at unusually high incident kinetic energies due to the overall enhanced
energy transfer from the incident atom to the lattice. Trapping probabilities
of Ar, Kr, and Xe are significantly lower on Ni(1�1�1) than on either
Pt(1�1�1) or Pd(1�1�1) despite the lower surface mass of the Ni atoms.
This result is attributed to the lower binding energy of the rare
gases on Ni(1�1�1) and the higher Debye temperature of Ni. The energy
scaling of Ar trapping on Ni(1�1�1) is determined by static corrugation,
but the energy scaling for Kr and Xe on Ni(1�1�1) may involve the
effects of dynamic corrugation. In the latter cases, the greater
stiffness of the nickel lattice decreases the dynamic corrugation
relative to Pt(1�1�1) and Pd(1�1�1).
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