Temperature dependence of polar-angle distributions of atoms ejected from ion-bombarded Au{111}

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Abstract
Molecular dynamics simulations incorporating the effect of temperature on the crystal lattice reproduce temperature-dependent changes in the ejection yield observed in experimentally obtained angular distributions of species ejected from the Au{111} surface. This effect has been only observed on fcc{111} surfaces and is preferentially active along the [110] direction. The underlying microscopic process responsible for the observed temperature-dependent change in the angular spectra is shown to be related to the number of direct ejection events occurring along close-packed crystallographic directions. Approximately 90% of the observed decrease in the yield along the [110] direction, with increased target temperature, results predominately from surface quenching with some minor contribution from subsurface misalignment of direct ejection sequence chains. The observations for Au{111} are generalized to predict the temperature dependence of the ejection yield for atoms ejected from low index metal single crystals. © 1996 The American Physical Society.