title: Intermediate-range chemical ordering of cations in molten RbCl-AgCl.
abstract: A first sharp diffraction peak (FSDP) is observed in the X-ray total structure factor of a molten mixture of RbCl-AgCl, while both pure melts of RbCl and AgCl do not exhibit FSDP individually. Molecular dynamics simulations were performed to investigate the origin of the FSDP with the polarizable ion model (PIM). Coexistence of covalent Ag-Cl and ionic Rb-Cl bonds leads the system to evolve intermediate range ordering, which is simulated by introducing the induced polarization in different ways between Ag-Cl with fully polarizable treatment based on Vashishta-Raman potential and Rb-Cl with suppression over-polarization in the nearest neighbor contribution based on Born-Meyer potential. The partial structure factors for both the Ag-Ag and Rb-Rb correlations, SAgAg(Q) and SRbRb(Q), show a positive contribution to the FSDP, while SAgRb(Q) for the Ag-Rb correlation exhibits a negative contribution, indicating that Ag and Rb ions are distributed in an alternating manner within the intermediate-range length scale. The origin of the intermediate-range chemical ordering of cations can be ascribed to the preferred direction of the dipole moments of anions in the PIM.
authors.affiliation: Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, Okinawa 903-0213, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tahara
authors.affiliation: J-PARC Center, Japan Atomic Energy Agency (JAEA), Ibaraki 319-1195, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kawakita
authors.affiliation: Faculty of Pharmacy, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shimakura
authors.affiliation: Research and Utilization Division, Japan Synchrotron Radiation Research Institute (JASRI, SPring-8), Hyogo 679-5198, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ohara
authors.affiliation: Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, Okinawa 903-0213, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fukami
authors.affiliation: Department of Physics, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Takeda
mesh_terms: D000838:Anions / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry*; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D012413:Rubidium / Q000737:chemistry*; D018030:Silver Compounds / Q000737:chemistry*; D013696:Temperature
chemical_list: D000838:Anions; D002412:Cations; D002712:Chlorides; D018030:Silver Compounds; D012413:Rubidium; C037548:silver chloride; C032710:rubidium chloride