title: Density measurements of noncrystalline materials at high pressure with diamond anvil cell.
abstract: We describe an x-ray absorption method for in situ density measurement of non-crystalline materials in the diamond anvil cell using a monochromatic synchrotron x-ray microbeam. Sample thickness, which is indispensable in the absorption method, can be determined precisely by extrapolating the thickness profile of the gasket obtained by x-ray absorption and diffraction measurements. Diamond deformation across the sample chamber becomes noticeable at high pressures above 10 GPa, which can be monitored with a precision better than 1%, as demonstrated by measurements on crystalline Ag. We have applied the developed method to measure densities of the classic network-forming GeO(2) glass in octahedral form at pressures up to 56 GPa. The fit to the pressure-volume data with the Birch-Murnaghan equation from 13 to 56 GPa gives parameters of V(0)=23.2+/-0.4 cm(3)mol and K=35.8+/-3.0 GPa, assuming that K(')=4. This method could be applicable for in situ determination of the density of liquids and other noncrystalline materials using a diamond anvil cell up to ultrahigh pressures.
authors.affiliation: Consortium for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, USA. xh48@cornell.edu
authors.forename: Xinguo
authors.initials: X
authors.lastname: Hong
authors.forename: Guoyin
authors.initials: G
authors.lastname: Shen
authors.forename: Vitali B
authors.initials: VB
authors.lastname: Prakapenka
authors.forename: Mark L
authors.initials: ML
authors.lastname: Rivers
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Sutton
mesh_terms: D015502:Absorptiometry, Photon / Q000295:instrumentation* / Q000379:methods; D003461:Crystallography; D018130:Diamond / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing / Q000295:instrumentation* / Q000379:methods; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000295:instrumentation* / Q000379:methods; D014961:X-Ray Diffraction / Q000295:instrumentation* / Q000379:methods
chemical_list: D018130:Diamond