Transition metal AB{sub 3} intermetallics: Structure maps based on quantum mechanical stability
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Room 160B, S. T. Olin Building, Ithaca, NY 14853-1301 (United States)
We study a two-dimensional structure map for AB{sub 3} binary transition metal compounds with variables appropriate for direct quantum-mechanical energy calculations. The variables are the electron count and {delta}H{sub ii}, the difference in d-orbital Coulombic integrals. The experimental structure map differentiates between the six known AB{sub 3} transition metal structure types: Cr{sub 3}Si,AuCu{sub 3},SnNi{sub 3},TiAl{sub 3},TiCu{sub 3} and TiNi{sub 3}. The theoretical quantum mechanical map (based on {mu}{sub 2}-Huckel calculations) gives good agreement with the experimental map. The numerical accuracy of the {mu}{sub 2}-Huckel energies is assessed by direct comparison to LDA-DFT calculations carried out on TaIr{sub 3}. For this system, both the {mu}{sub 2}-Huckel and LDA-DFT calculations place the six structure types in the same energetic order. The {mu}{sub 2}-Huckel theory, in addition, allows further analysis on the structural origins of these differences in energy. The chief structural features responsible for differences in energy prove to be the varying number of three- and four-member rings of bonded atoms. These results help delineate the principal factors responsible for transition metal icosahedral, Frank-Kasper vs. closest-packed structures.
- OSTI ID:
- 20725899
- Journal Information:
- Journal of Solid State Chemistry, Vol. 178, Issue 4; Other Information: DOI: 10.1016/j.jssc.2004.12.044; PII: S0022-4596(04)00670-X; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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