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Simulations of core excitation in energetic cluster impacts on metallic surfaces

Shapiro, M. H. and Tombrello, T. A. (1992) Simulations of core excitation in energetic cluster impacts on metallic surfaces. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 66 (3). pp. 317-324. ISSN 0168-583X. doi:10.1016/0168-583X(92)95991-Y. https://resolver.caltech.edu/CaltechAUTHORS:20141021-155910695

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Abstract

A modified version of the SPUT2 molecular dynamics sputtering code was used to investigate core excitation in Al atoms following the impact of pure Al clusters and composite Al-Au clusters on Au surfaces. Information was obtained on distances-of closest-approach times-of-closest-approach, and ejection properties of cluster-atoms undergoing hard collisions for 32-, 63-, and 108-atom Al clusters impacting Au(100) targets with energies/atom ranging from 0.2 keV to 1.0 keV. Similar information was obtained for composite Al-Au clusters (38 Al atoms, 25 Au atoms) with comparable total cluster energies. Using a simple critical distance model (R_c = 0.44 Å) for L-shell core excitation in Al, the threshold for core excitation in pure Al clusters was found to be at approximately 0.4 keV/atom. For the composite clusters, the threshold was at approximately 0.11 keV/Al-atom. Core excitation was most probable during the early, compressional phase of the cluster impacts. A significant fraction (typically ∼40%) of core-excited Al atoms were found to eject from the cluster-target system. Elapsed times between excitation and ejection typically were less than 80 fs, and significant numbers of Al atoms ejected within 20–30 fs after excitation. Our results suggest that line spectra of Auger electrons from sputtered, excited cluster-atoms can be used as a diagnostic tool to investigate the early stages of energetic cluster collisions with surfaces.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/0168-583X(92)95991-Y DOIArticle
http://www.sciencedirect.com/science/article/pii/0168583X9295991YPublisherArticle
Additional Information:© 1992 Elsevier Science Publishers B.V. Received 9 September 1991 and in revised form 6 November 1991. Supported in part by NSF Grant DMR90-11230 at Caltech, and by NSF Grant DMR90-02532 at CSUF. The authors thank the referee for helpful comments regarding the manuscript.
Funders:
Funding AgencyGrant Number
NSFDMR90-11230
NSFDMR90-02532
Issue or Number:3
DOI:10.1016/0168-583X(92)95991-Y
Record Number:CaltechAUTHORS:20141021-155910695
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141021-155910695
Official Citation:M.H. Shapiro, T.A. Tombrello, Simulations of core excitation in energetic cluster impacts on metallic surfaces, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Volume 66, Issue 3, 2 April 1992, Pages 317-324, ISSN 0168-583X, http://dx.doi.org/10.1016/0168-583X(92)95991-Y. (http://www.sciencedirect.com/science/article/pii/0168583X9295991Y)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50644
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:22 Oct 2014 16:48
Last Modified:10 Nov 2021 18:58

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