8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Fri 911:10-14:00P1.35Short- and intermediate-range structure analysis forliquid Cs-Au mixtures by using Reverse Monte CarlomodelingSatoshi Sato 11 Niigata University, 8050, Ikarashi-2, Nishi-ku, 950-2181, Niigata, JapanRecent years, much attention has been paid on certain liquid alloys which exhibit a metal-nonmetaltransition around a stoichiometric compositions, through both components are metallic conductors.Liquid Au-Cs system is a typical example of such alloys. The computer simulation investigationshave been performed on this liquid mixtures. Some of them showed the different partial structuremodels. In this study, we performed Reverse Monte Carlo (RMC) modeling for liquid Cs 50 Au 50to investigate partial structure in this system based on the neutron scattering data [1]. The appliedconstraint was only the limitation of the shortest interatomic distances. Two types of restrictiondetermined by the results of molecular dynamics (MD) were applied. One was based on the classicalMD simulation [2], and the shortest distances were set to be 3.3Å, 2.98Å and 2.5Å forCs-Cs, Au-Au and Cs-Au pairs, respectively. For another simulation based on the quantum moleculardynamics (QMD)[3] the closest distances were set to be 3.3Å, 2.4Å and 2.7Å, respectively.Comparing the pair distribution functions obtained from the structure models, it was suggestedthat model corresponding to the QMD was more reasonable one. We have analyzed the coordinationnumbers and the bond-angles of the atom pairs, which suggested that the local structure ofCs 50 Au 50 was different of the CsCl type structure of simple ionic mixtures. The structure modelsof liquid Cs-Au mixtures at the different concentrations were also created. The local and intermediatestructure of liquid Cs-Au mixtures was investigated based on the void structure and the bondorientation order. [1] W. Martin et al. : J. Phys. Chem. Liq. , 10 (1980) 49-83 [2] S. Matsunaga: J.Phys. Soc. Jpn. , 69 (2000) 1712-1716 [3] N. Charpentier et al. : Phys. Rev. B, 78 (2008) 10020235