File format reference
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:
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