Publication:
Atomic and molecular ejection from ion-bombarded reacted single-crystal surfaces. Oxygen on copper(100)

Authors
Garrison, B.J.
Winograd, N.
Harrison, D.E. Jr.
Subjects
Advisors
Date of Issue
1978-12-01
Date
Publisher
American Physical Society
Language
Abstract
The trajectories of atomic and molecular species ejected from an ion-bombarded reacted single-crystal surface have been calculated using classical dynamics. As a model system, oxygen has been adsorbed in various coverages and site geometries of the (100) face of a copper surface, which is them bombarded by 600-vY Ar+ ions at normal incidence. The oxygen atoms have been placed at near zero (single-atom adsorption), p(2X2) and c(2X2) coverages in an A-top site, a fourfold bridge site, and a twofold bridge site. From the calculated positions and moments of the ejected adsorbate and substrate atoms, we have identified the important ejection mechanisms, determined relative yields, and determined the factors that influence multimer formation. Of mechanistic interest is that oxygen is most often ejected by collisions with an adjacent copper atom rather than by collisions with the copper atom directly beneath it. The calculation show that multimers of the types Cu(2), CuO, O(2), Cu(2)O, and O(3), and several tetramers and pentamers can be expected to form. These multimers establish their identity over the surface and do not directly eject as a molecular entity. The influence of site geometry on multimer yields is discusses in detail. In general, the bridge sites have higher multimer yields that the A-top site. The surface coverage also exerts a systematic influence on the types of clusters that are observed. For example, molecules like O(2) and CuO(2) are not likely to be ejected from a p(2X2) surface due to a large O-O separation distance.
Type
Article
Description
Series/Report No
Department
Physics and Chemistry
Other Units
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
NSF under Grant No. MPS75-9308, and the Materials Research Program under Grant No. DMR-77-23798 and the U.S. Air Force.
Funder
Format
11 p.
Citation
Physical Review B, V. 18, no.11, December 1, 1978, pp. 1600-1610
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.