Surface Structure of Bi(111) from Helium Atom Scattering Measurements. Inelastic Close-Coupling Formalism

8 págs.; 4 figs.; 2 tabs.; Open Access funded by Creative Commons Atribution Licence 4.0© 2015 American Chemical Society. Elastic and inelastic close-coupling (CC) calculations have been used to extract information about the corrugation amplitude and the surface vibrational atomic displacement by fitting to several experimental diffraction patterns. To model the three-dimensional interaction between the He atom and the Bi(111) surface under investigation, a corrugated Morse potential has been assumed. Two different types of calculations are used to obtain theoretical diffraction intensities at three surface temperatures along the two symmetry directions. Type one consists of solving the elastic CC (eCC) and attenuating the corresponding diffraction intensities by a global Debye-Waller (DW) factor. The second one, within a unitary theory, is derived from merely solving the inelastic CC (iCC) equations, where no DW factor is necessary to include. While both methods arrive at similar predictions for the peak-to-peak corrugation value, the variance of the value obtained by the iCC method is much better. Furthermore, the more extensive calculation is better suited to model the temperature induced signal asymmetries and renders the inclusion for a second Debye temperature for the diffraction peaks futile.This research was supported by the European Commission and the Styrian Government within the ERDF program. S.M.A. acknowledges MICINN (Spain) through Grant No. FIS2011- 29596-C02-01. A.T. acknowledges financial support provided by the FWF (Austrian Science Fund) within the project J3479- N20.Peer Reviewe

A comparative study of the He-Sb(111) interaction potential from close-coupling calculations and helium atom scattering experiments

8 pags.; 4 figs.; 3 tabs.; 1 app.© 2014 Elsevier B.V. All rights reserved. The exact elastic close-coupling formalism is used to compare the performance of several interaction potentials suggested in literature for describing the measured elastic diffraction peak intensities in helium scattering experiments. The coupling parameters have been analytically calculated for the corrugated Morse potential on a hexagonal surface structure and adapted for usage with similar interaction potentials. The potentials used have been fitted to previously known bound state energies complemented by two additional levels which are found by improving energy resolution. It is established that the shifted Morse potential reproduces the experimental He-Sb(111) bound state more closely than the other considered potential shapes. The performance of several interaction potentials in describing the elastic scattering intensities is presented and discussed. Morse and Morse-related potentials provide the best compromise for the description of elastic scattering intensities. The different effects of the potential shape were determined by comparing the calculated scattering intensities.This research was supported by the European Commission and the Styrian Government within the ERDF program. SMA wants to acknowledge MICINN (Spain) through Grant FIS2011-29596-C02-01.Peer Reviewe