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High‐pressure single‐crystal neutron diffraction (to 20 kbar) using a pulsed source: preliminary investigation of Tl 3 PSe 4
Author(s) -
Alkire R. W.,
Larson A. C.,
Vergamini P. J.,
Schirber J. E.,
Morosin B.
Publication year - 1985
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889885010007
Subject(s) - neutron diffraction , orthorhombic crystal system , bragg's law , lattice constant , compressibility , anisotropy , single crystal , neutron , neutron scattering , monoclinic crystal system , lattice (music) , chemistry , neutron source , diffraction , materials science , crystallography , crystal structure , optics , physics , nuclear physics , thermodynamics , acoustics
A new technique is described for performing high‐pressure single‐crystal neutron diffraction [up to 20 kbar (2 GPa) at room temperature], using a BeCu pressure cell, an area detector and the Los Alamos National Laboratory pulsed neutron source. Success of this method depends on the increase in information available with a multi‐wavelength pulse neutron source, a novel orientation of a cylindrically symmetric pressure cell with its axis coincident with the neutron beam and a specific crystal orientation within the pressure cell. Bragg scattering from the pressure cell is avoided and background for a given 2 θ is constant. For a crystal of orthorhombic or higher symmetry oriented with the incident beam passing midway between the major lattice vectors, it will be possible to refine a complete three‐dimensional structure with data collected from only one pressure loading. Preliminary investigations of Tl 3 PSe 4 lattice parameters (space group Pcmn ) at 15(1)kbar yielded linear compressibilities (× 1000 in kbar −1 ) of K a = 1.05(8), K b = 1.50(10), K c = 1.20(8). The anisotropic compressibility is explained by examination of the ambient‐pressure room‐temperature structure.