To read ARRNGE files and prepare for LSQ with extinction
Description:
-
The program will read one or more of the files written by ARRNGE or ARRINC
and prepare a file for LSQ in which equivalent reflections are treated
independently so that a path-length dependent extinction correction can be
refined. It will average reflections which have been measured more
than once. If the data are intensity measurements, and
"G" cards
are
present on the crystal data file, absorption factors will be calculated and
applied. In all cases the 4 constants needed for Becker Coppens extinction
corrections will be calculated. If no
"G" cards
are present a standard path
length of 2mm is used. The data are written in a form suitable for input
to the CCSL least squares programs (SFLSQ, MAGLSQ etc.).
Input:
-
The crystal data file must contain:
-
S cards
giving the symmetry
A
C card
with the cell dimensions
An
I DTYP card
describing the type of data (the same as used for
- ARRNGE) it is only used to determine whether the data are flipping
ratios or intensities and how many additional parameters such as
angles were stored by ARRNGE
An
E card
indicating which type of extinction is to be used (Gausssian,
- Lorentzian etc.)
D cards
describing the diffraction geometry
G cards
describing the crystal shape. These are optional and if absent no
- absorption corrections will be made and a constant path
length of 2mm will be assumed.
If the data are for a magnetic structure with non-integer indices
a
Q PROP card
giving the propagation vector is required.
Basically the same crystal data as that used with ARRNGE to produce the
input file should be used but with the addition of E, D and
G cards
. The
data input is one or more files written by one of the ARRNGE type
programs. Different files may correspond to different measurement
wavelengths, but they should all have the same crystal orientation and
measurement geometry.
Output:
-
The usual listing file reporting data read from the CDF. A file of
averaged and (possibly absorption corrected) data suitable for input to
one of the least squares programs L MODE 5 for integer indices and L MODE 8
for floating indices. This file has default extension .sf for
structure factors and .fr for flipping ratios.
Notes:
-
This program replaces the three similar programs ABSEXF, ARREXF and AVEXTR
Running the program:
-
On running the program the user is asked for the name of the crystal data
file and then for each data file: its name, the measurement wavelength
and a possible scale factor. This latter is to allow data on very
different scales to be scaled to approximately the same level, a scale of
unity is usually OK. Each data set will be given a different scaling code
so there should be one entry on the
L SCAL card
for each set.
Calls:
- ASK
DUMMY
ERRMES
ICDFMT
INPUAR
INPUTI
LENGT
NOPFIL
ONCARD
PATHS
PREFIN
RDREAL
RDWORD
RECIP
SETABS
SYMOP
Common blocks used:
-
- /ABSDAT/ to use MODEA
- /IOUNIT/ to use LPT ITO LUNI
- /REFS/ to use SCALE INC ITEMS
- /SCRACH/ to use all members
*** AVEXAR by PJB 14-Nov-1997 ***
Classification:
Data Collection and Reduction . . . . . . . Main Program
Calls:
- ABMULT
EXTPAR
GMEQ
INDFIX
WTMEAN
Called by:
- AVEXAR
Common blocks used:
-
- /DIRCOS/ to use all members
- /EXTN/ to use CEXT
- /IOUNIT/ to use LPT LUNI
- /REFS/ to use LL SCALE INC II
- /STATS/ to use WRK2
*** PATHS by PJB 10 Apr 87 ***
P. Jane Brown
e-mail: brown@ill.fr
Institut Laue Langevin,
Grenoble, FRANCE