Excitation of the shear horizontal mode in a monolayer by inelastic helium atom scattering

L. W. Bruch, Flemming Yssing Hansen

Research output: Contribution to journalJournal articleResearchpeer-review

221 Downloads (Pure)

Abstract

Inelastic scattering of a low-energy atomic helium beam (HAS) by a physisorbed monolayer is treated in the one-phonon approximation using a time-dependent wave,packet formulation. The calculations show that modes with shear horizontal polarization can be excited near high symmetry azimuths of the monolayer, in agreement with recent experiments. The parameters of the calculations are chosen to match the conditions of HAS experiments for triangular incommensurate monolayer solids of xenon, krypton, and argon adsorbed on the (111) face of platinum, and the results show many of the systematic experimental trends for relative excitation probability of the shear horizontal and longitudinal acoustic phonon branches. The inelastic scattering at beam energies near 8 meV is exceedingly sensitive to small misalignment between the scattering plane and the high symmetry directions of the monolayer solid. The diffraction and inelastic processes arise from a strong coupling of the incident atom to the target and the calculated results show large departures from expectations based on analogies to inelastic thermal neutron scattering.
Original languageEnglish
JournalJournal of Chemical Physics
Volume122
Issue number11
Pages (from-to)114714
ISSN0021-9606
DOIs
Publication statusPublished - 2005

Bibliographical note

Copyright (2005) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

Fingerprint Dive into the research topics of 'Excitation of the shear horizontal mode in a monolayer by inelastic helium atom scattering'. Together they form a unique fingerprint.

Cite this