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A simple fortran program to interpret cubic X-ray prowder diffraction data
C-383 Computer Physics Communications 11 (1976) 331-337 © North-Holland Publishing Company
A SIMPLE F O R T R A N P R O G R A M TO I N T E R P R E T CUBIC X - R A Y POWDER D I F F R A C T I O N DATA E.D. yon M E E R W A L L
Physics Department, The University of Akron, Akron, Ohio 44325, USA Received 1 July 1976
PROGRAM SUMMARY
Title of program: XRAY2 Catalogue number: ABMT Computer: IBM 370/158; hTstallation: The University of Akron, Akron, Ohio, USA
bic lattices whose dimensions are known approximately. For cubic types, a careful determination of the lattice parameter is made.
Method of solution
High speed store required: 8700 words (35 kbt)
The Bragg equation with given parameters is inverted to give primitive plane spacings, which are then associated with the nearest (if acceptable) observed lines by indices and order. For cubic types, a Taylor-Sinclair extrapolation of the lattice parameter is made, based on the identified lines.
Number of bits in a word: 32
Restrictions on program complexity
Overlay structure: no ne
The present limit of 50 observed lines is easily removed by redimensioning and altering one loop parameter.
Operating system: OS/MVT, OS/VS2 Programming language used: FORTRAN IV (G)
Number of magnetic tapes required: None Other peripherals used: card reader, line printer Number o f cards in combined program and test deck: 618
Keywords: Crystallography, X-ray, diffraction, powder method, Debye-Scherrer, indexing, cubic lattice, orthorhombic, tetragonal, lattice parameter fit.
Nature of physical problem Powder X-ray diffraction data can be tested for the presence and approximate amount of cubic, tetragonal, or orthorhom-
Typical running time On the IBM 370/158, the program compiles (G level) in about 3 CPU sec. A typical case with 15 lines, a limit on reflection indices of six, and two hypotheses, takes about 1 see CPU time.
Unusual features of the program The program is intended as an aid in identifying powder diffraction patterns, and to make precision measurements of cubic lattice parameters. (1) Line positions are accepted either as angles O or as cm readings on film; in the latter case, the e = 0 position (and f'dm shrinkage) may be found by the program and (2) several hypothetical structures per spectrum may be tested for; line intensities are not used in the identification, but only to estimate relative identified intensity.
A SIMPLE F O R T R A N P R O G R A M TO I N T E R P R E T CUBIC X - R A Y POWDER D I F F R A C T I O N DATA E.D. yon M E E R W A L L
Physics Department, The University of Akron, Akron, Ohio 44325, USA Received 1 July 1976
PROGRAM SUMMARY
Title of program: XRAY2 Catalogue number: ABMT Computer: IBM 370/158; hTstallation: The University of Akron, Akron, Ohio, USA
bic lattices whose dimensions are known approximately. For cubic types, a careful determination of the lattice parameter is made.
Method of solution
High speed store required: 8700 words (35 kbt)
The Bragg equation with given parameters is inverted to give primitive plane spacings, which are then associated with the nearest (if acceptable) observed lines by indices and order. For cubic types, a Taylor-Sinclair extrapolation of the lattice parameter is made, based on the identified lines.
Number of bits in a word: 32
Restrictions on program complexity
Overlay structure: no ne
The present limit of 50 observed lines is easily removed by redimensioning and altering one loop parameter.
Operating system: OS/MVT, OS/VS2 Programming language used: FORTRAN IV (G)
Number of magnetic tapes required: None Other peripherals used: card reader, line printer Number o f cards in combined program and test deck: 618
Keywords: Crystallography, X-ray, diffraction, powder method, Debye-Scherrer, indexing, cubic lattice, orthorhombic, tetragonal, lattice parameter fit.
Nature of physical problem Powder X-ray diffraction data can be tested for the presence and approximate amount of cubic, tetragonal, or orthorhom-
Typical running time On the IBM 370/158, the program compiles (G level) in about 3 CPU sec. A typical case with 15 lines, a limit on reflection indices of six, and two hypotheses, takes about 1 see CPU time.
Unusual features of the program The program is intended as an aid in identifying powder diffraction patterns, and to make precision measurements of cubic lattice parameters. (1) Line positions are accepted either as angles O or as cm readings on film; in the latter case, the e = 0 position (and f'dm shrinkage) may be found by the program and (2) several hypothetical structures per spectrum may be tested for; line intensities are not used in the identification, but only to estimate relative identified intensity.