title: In situ XAFS and XRD studies of pressure-induced local structural change in liquid AgI.
abstract: In order to examine the pressure-induced structural change of liquid silver iodide (AgI), high-pressure and high-temperature in situ x-ray absorption fine structure (XAFS) and x-ray diffraction (XRD) studies have been carried out up to 1200 K and 6 GPa. The modifications in the x-ray absorption near edge structure (XANES) spectra and x-ray structure factors, S(Q), with increasing pressure provide evidence for changes in the short-range order of liquid AgI. The I-Ag bond length in liquid AgI increases by compression up to 2 GPa, which proposes that components with higher coordination than fourfold are introduced. The I-Ag bond length decreases monotonically with compression above 2 GPa, indicating that the structural change involving a coordination-number change is completed below 2 GPa and then a high-pressure form of liquid AgI is stabilized. Comparing the I-Ag bond lengths of liquid AgI with those of crystalline phases, we conclude that the high-pressure form of liquid AgI has a rocksalt-like structure with large vacancies.
authors.affiliation: Earth and Space Science, Osaka University, Toyonaka, Osaka 560-0043, Japan. arima@ess.sci.osaka-u.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Arima
authors.forename: O
authors.initials: O
authors.lastname: Ohtaka
authors.forename: T
authors.initials: T
authors.lastname: Hattori
authors.forename: Y
authors.initials: Y
authors.lastname: Katayama
authors.forename: W
authors.initials: W
authors.lastname: Utsumi
authors.forename: A
authors.initials: A
authors.lastname: Yoshiasa