title: High Pressure Single Crystal Diffraction at PX^2.
abstract: In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the GSECARS 13-BM-C beamline at the Advanced Photon Source. The DAC program at 13-BM-C is part of the Partnership for Extreme Xtallography (PX^2) project. BX-90 type DACs with conical-type diamond anvils and backing plates are recommended for these experiments. The sample chamber should be loaded with noble gas to maintain a hydrostatic pressure environment. The sample is aligned to the rotation center of the diffraction goniometer. The MARCCD area detector is calibrated with a powder diffraction pattern from LaB6. The sample diffraction peaks are analyzed with the ATREX software program, and are then indexed with the RSV software program. RSV is used to refine the UB matrix of the single crystal, and with this information and the peak prediction function, more diffraction peaks can be located. Representative single crystal diffraction data from an omphacite (Ca0.51Na0.48)(Mg0.44Al0.44Fe2+0.14Fe3+0.02)Si2O6 sample were collected. Analysis of the data gave a monoclinic lattice with P2/n space group at 0.35 GPa, and the lattice parameters were found to be: a = 9.496 ±0.006 Å, b = 8.761 ±0.004 Å, c = 5.248 ±0.001 Å, β = 105.06 ±0.03º, α = γ = 90º.
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Manoa; dzhang@hawaii.edu.
authors.forename: Dongzhou
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Manoa.
authors.forename: Przemyslaw K
authors.initials: PK
authors.lastname: Dera
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Eng
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago.
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Stubbs
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Manoa.
authors.forename: Jin S
authors.initials: JS
authors.lastname: Zhang
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago.
authors.forename: Vitali B
authors.initials: VB
authors.lastname: Prakapenka
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Rivers
mesh_terms: D018360:Crystallography, X-Ray / Q000379:methods*; D018130:Diamond / Q000737:chemistry; D033362:Powder Diffraction; D011312:Pressure; D017356:Synchrotrons
chemical_list: D018130:Diamond