Electron charge distribution of CaAl{sub 2-x}Zn{sub x}: Maximum entropy method combined with Rietveld analysis of high-resolution-synchrotron X-ray powder diffraction data

Journal Article · Fri Aug 15 00:00:00 EDT 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.04.034· OSTI ID:21128403

Soederberg, Karin ^[1]; Kubota, Yoshiki ^[2]; Muroyama, Norihiro; Gruener, Daniel ^[1]; Yoshimura, Arisa ^[2]; Terasaki, Osamu ^[1]

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1. Arrhenius Laboratory, Department of Physical, Inorganic and Structural Chemistry, Stockholm University, Stockholm 10691 (Sweden)
2. Graduate School of Science, Department of Physical Science, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan)

Using short wavelength X-rays from synchrotron radiation (SPring-8), high-resolution powder diffraction patterns were collected. In order to study both the structural relationship and the mechanism of stability in the CaAl{sub 2-x}Zn{sub x} system, among the Laves phases (MgCu{sub 2} and MgNi{sub 2} type) and KHg{sub 2}-type structures, the charge density distribution of CaAl{sub 2-x}Zn{sub x} as a function of x was obtained from the diffraction data by Rietveld analysis combined with the maximum entropy method (MEM). In the MEM charge density maps overlapping electron densities were clearly observed, especially in the Kagome nets of the Laves phases. In order to clarify the charge redistribution in the system, the deformation charge densities from the densities formed by the constituent free atoms are discussed. In the ternary MgNi{sub 2}-type phase, partial ordering of Al and Zn atoms is observed, a finding that is supported by ab-initio total energy calculations. - Graphical abstract: Using short wavelength X-rays from synchrotron radiation (SPring-8), high-resolution powder diffraction patterns of the Laves (MgCu{sub 2} and MgNi{sub 2} type) and KHg{sub 2}-type phases in the CaAl{sub 2-x}Zn{sub x} system were collected. The charge density distribution in the Laves phases as a function of x was obtained from the diffraction data by Rietveld analysis combined with the maximum entropy method (MEM)

• OSTI ID: 21128403
• Journal Information: Journal of Solid State Chemistry, Vol. 181, Issue 8; Other Information: DOI: 10.1016/j.jssc.2008.04.034; PII: S0022-4596(08)00213-2; Copyright (c) 2008 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

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM COMPOUNDS
CALCIUM COMPOUNDS
CALCULATION METHODS
CHARGE DENSITY
CHARGE DISTRIBUTION
ELECTRON DENSITY
ELECTRONS
ENTROPY
INTERMETALLIC COMPOUNDS
LAVES PHASES
SPRING-8 STORAGE RING
SYNCHROTRON RADIATION
X RADIATION
X-RAY DIFFRACTION
ZINC COMPOUNDS