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PROGRAM CHILSQ

Least squares refinement from magnetic structure factor data
(paramagnetic version)

Description:

Main program for least squares refinement, of magnetic structure factor data from (possibly) mixed nuclear and magnetic reflections
Paramagnetic structure factors with anisotropic susceptibility

Input:

The crystal data file must contain all cards needed for magnetic and nuclear structure factor calculations vis:
S cards giving the symmetry.
A C card with the cell dimensions.
A cards defining the atoms, their positions and isotropic. temperature factors.
F cards giving the magnetic and non-magnetic scattering factors
Q cards defining the magnetic structure (Q STYP PARA)
optionally:
T cards giving anisotropic temperature factors

Additionally:
L cards indicating which parameters should be refined
REFI = 3 paramagnetic intensities
REFI = 5 flipping ratios
REFI = 7 asymmetries
REFI =11 magnetised powder intensities are useful (see the CCSL users' manual)
I cards which may have the words words NCYC, CYCL1, PRIN,
MCOR and CONV
NCYC the number of least squares cycles (default 3)
CYC1 the number to be assigned to the first cycle (default 1)
PRIN frequency at which output lists are printed
PRIN = 0 no printing
PRIN = 1 first cycle
PRIN = 2 last cycle
PRIN = 3 first and last cycles
PRIN = 4 every cycle

MCOR controls the correlations printed at the end of the job
(default +70)
MCOR = 0 whole correlation matrix printed
MCOR = -ve no printing
MCOR = +ve correlations above MCOR printed

CONV convergence criterion; LSQ cycling is terminated if the
maximum shift/esd < CONV (default 0.01)

The data file which should be a list of hkl and structure factors or flipping ratios in the format indicated by the L MODE and REFI cards .

Output:

The usual listing file reporting the data which have been read. This file also contains the output listings requested by the I PRIN card as well as the R-factors and chisqrd at the end of each least squares cycle.
A new crystal data file corresponding to the structure at the end of the least squares refinement.

Running the program:

On running the program the user is asked for the name of the crystal data file and the name of the file containing the structure factor data.
The value of \$\chi^2\$ at the end of each cycle is reported on the terminal.
Just before the last cycle the user is asked for a name for the new crystal data file.

Calls:

APSHSF CALCFR CALCMG CALPOW CENTRE CHITRN DFLTCH ERRMES GMEQ INDFIX LFCALC LSETSF MATCOR MATINV MATSET MATSHF MATTOT MUCALC NWINSF PARRUN PARSSF PREFIN PRNCYC RELATE RFACS SETABS SETFCM STLSSF TCHALC VARMAK VARSSF WGHTSF

Common blocks used:

/DERBAS/ to use LVARB
/DSOURC/ to use NUMSRC JSRC MSRC NOBSRC SRCPAR
/EXTN/ to use IEXTYP CEXT PATHS
/FCAL/ to use FCMOD
/IOUNIT/ to use LPT ITO
/MAGCHI/ to use FIELD
/MCAL/ to use FMCMOD
/NEWOLD/ to use AMAXSH
/OBSCAL/ to use OBS GCALC YCALC DIFF SUMWD WT
/POLDA/ to use POLUP POLDW POLND
/POSNS/ to use NATOM
/PRBLEM/ to use NFAM LF1SP
/REFINE/ to use IREF NCYC NCYC1 LASTCY ICYC MAG CONV
/SCLDAT/ to use ISCALE SCALE
/SFDATA/ to use all members
/SFHEDC/ to use all members
/SFHEDP/ to use all members

*** CHILSQ updated to allow structure factor refinement C4.11 Oct 2008 ***

Classification:

General Least Squares Refinement . . . . . . . Main Program

LOGICAL FUNCTION DFLTCH(IFAM,IGEN,ISPC)

Calls:

DFLTCH

Called by:

CHILSQ DFLTCH

Common blocks used:

/MAGDAT/ to use MAGAT




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P. Jane Brown

Institut Laue Langevin,
Grenoble, FRANCE