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PROGRAM MAGPOW

To generate indices of reflections in a magnetic powder diagram

Description:

MAGPOW reads a crystal data file and, using a wavelength given interactively, calculates the angles 2\$\theta\$, at which reflections will occur. For each reflection the square of the structure factor, the multiplicity, the factor relating \$F^2\$ to intensity, and the intensity of the corresponding powder line are tabulated.

Input:

The crystal data file must contain:
S card (s) giving the space group symmetry (note that a single card saying "S GRUP n" card should suffice n is the space group number)
A C card with the cell dimensions
A cards with the atomic positions
F cards with the form factors or scattering lengths
Q cards to define the magnetic structure

Output:

A listing file: magpow.lis which reports how the crystal data file was interpreted and gives the results of the calculation. The results columns and their headings are:
h k l: for the magnetic reflection indices
H K L: the indices of the fundamental from which
the reflection is derived, followed by + or - to indicate whether the propagation vector was added or subtracted.
2theta: the scattering angle
FNsqr: the square of the nuclear structure factor
FMsqr: the square of the magnetic structure factor
Intensity: The expected intensity of the powder line

The format of the results file, if one is requested is (5I5) It contains, for each reflection, the indices h, k, l of the fundamental reflection from which it is derived, 1, -1 or 0 to indicate whether the propagation vector is to be added, subtracted or not used; the final number gives the multiplicity.

Running the program:

On running the program the user is asked for the name of the crystal data data file, the wavelength, the maximum and optionally the minimum 2\$\theta\$ for which results are required; also whether the results should be written to a file and so the name of the file.

Calls:

ASK CENTRE CGMZER DEGREE ERRMES FCALC FMCALC GENMAG GENMUL GMADD GMEQ GMSUB INDFIX JFIX LATABS MAGABS MAGCNC MESS NOPFIL PREFIN RADIAN RDNUMS SAYS SETFCM SETGEN SORTN SYMBAK SYMUNI TESTP VCTMOD

Common blocks used:

/BRAGG/ to use STHL
/IOUNIT/ to use LPT ITO
/SATELL/ to use PROP NKSTAR IPROP
/SCRACH/ to use NAMFIL

*** MAGPOW by PJB March 1994 ***

Classification:

Magnetic Structure Factors . . . . . . . Main Program


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P. Jane Brown e-mail: brown@ill.fr
Institut Laue Langevin,
Grenoble, FRANCE