Time-of-flight studies on desorbing and on scattered D sub 2 molecules from a V(111) + S surface

Using a time-of-flight spectrometer we have measured the translational energy distribution of deuterium molecules originating from a sulfur-covered vanadium(111) surface. We have studied the energy accommodation coefficient (EAC) of D sub 2 after scattering of a room temperature D sub 2 gas on the s...

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Bibliographic Details
Published in:Surface science 2000-09, Vol.482-485 (1), p.201-206
Main Authors: Eibl, C, Winkler, A
Format: Article
Language:English
Online Access:Get full text
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Summary:Using a time-of-flight spectrometer we have measured the translational energy distribution of deuterium molecules originating from a sulfur-covered vanadium(111) surface. We have studied the energy accommodation coefficient (EAC) of D sub 2 after scattering of a room temperature D sub 2 gas on the surface. An EAC of 0.37, independent of the surface temperature, is obtained. Furthermore, we have investigated the mean translational energy of D sub 2 molecules desorbing isothermally from the surface at 950 K. A hyperthermal desorption flux has been observed, corresponding roughly to a Maxwellian of 3200 K. From these results we conclude that the potential energy surface for the D sub 2 -V(111) + S system is characterized by an activation barrier for dissociative adsorption of about 0.22 eV and a non-existing physisorption well in front of the barrier.
ISSN:0039-6028