Simulation of high pressure diffraction patterns: JCPDS Card, version 4

This applet can read JCPDS cards, version 4, with high pressure data. I did not invent the format and I copied the specs from high pressure beamlines at the APS. I think you have to thank (or blame!) Mark Rivers or Dan Shim for it...

There are several versions of the formats used for JCPDS files. Versions 1, 2 and 3 used a fixed format, where a particular entry had to be in a specific location on a specific line. Versions 2 and 3 were used only by Dan Shim. Version 4 is a "keyword" driven format. Each line in the file is of the form:

KEYWORD: value

The order of the lines is not important, except that the first line of the file must be "VERSION: 4".

The following keywords are currently supported:

           COMMENT:    Any information describing the material, literature
                       references, etc.  There can be multiple comment lines
                       per file.
           K0:         The bulk modulus in GPa.
           K0P:        The change in K0 with pressure, for Birch-Murnaghan
                       equation of state.  Dimensionless.
           DK0DT:      The temperature derivative of K0, GPa/K.
           DK0PDT:     The temperature derivative of K0P, 1/K.
           SYMMETRY:   One of CUBIC, TETRAGONAL, HEXAGONAL, RHOMBOHEDRAL,
                       ORTHORHOMBIC, MONOCLINIC or TRICLINIC
           A:          The unit cell dimension A
           B:          The unit cell dimension B
           C:          The unit cell dimension C
           ALPHA:      The unit cell angle ALPHA
           BETA:       The unit cell angle BETA
           GAMMA:      The unit cell angle GAMMA
           VOLUME:     The unit cell volume
           ALPHAT:     The thermal expansion coefficient, 1/K
           DALPHADT:   The temperature derivative of the thermal expansion
                       coefficient, 1/K^2
           DIHKL:      For each reflection, the D spacing in Angstrom, the
                       relative intensity (0-100), and the H, K, L indices.

The following is an example JCPDS file in the Version 4 format:

           VERSION:  4
           COMMENT: Alumina (JCPDS 0-173, EOS n/a)
           K0:          194.000
           K0P:           5.000
           SYMMETRY: HEXAGONAL
           A:            4.758
           C:            12.99
           VOLUME:        22.0640
           ALPHAT:    2.000e-6
           DIHKL:        3.4790      75.0   0   1   2
           DIHKL:        2.5520      90.0   1   0   4
           DIHKL:        2.3790      40.0   1   1   0
           DIHKL:        2.0850     100.0   1   1   3
           DIHKL:        1.7400      45.0   0   2   4
           DIHKL:        1.6010      80.0   1   1   6
           DIHKL:        1.4040      30.0   2   1   4
           DIHKL:        1.3740      50.0   3   0   0
           DIHKL:        1.2390      16.0   1   0  10

Sebastien Merkel, 02/2006
 

© Sébastien Merkel, Université de Lille, France

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