PROGRAM GENREF

To generate reflections and create a D3 measuring file

Description:

The program generates reflections and creates a D3 measuring file with extension ".ips" containing those which satisfy specified criteria. If the filename requested is XXXXXn the last instruction in the measuring file is *CIS XXXXXm where m=n+1. Only reflections having accessible setting angles are included.
The following criteria can be selected interactively by the user

A. The minimum and maximum \$\nu\$ (angle of elevation of the detector)
B. The maximum \$\rho\$ (angle of elevation of the scattering vector)
C. The minimum and maximum \sinth
D. The minimum and maximum nuclear structure factors
E. The maximum number of equivalent reflections included
F. The frequency of measurement of the standard reflection
G. Lower and upper limits for \$\gamma\$ (the detector angle 2\$\theta\$ for \$\nu=0\$)

Standard reflection measurements can be included at requested intervals

Input:

The crystal data file must contain:

Symmetry information on S cards
The unit cell definition on a C card
The atomic positions on A cards
The nuclear scattering lengths on F cards
The wavelength, geometry definition and UB matrix on D cards these can be copied from the final set on the file "dcards.cry" created by D3OP97.

Output:

A listing file: "genref.lis: which reports how the crystal data file was interpreted and lists the reflections to be measured together with their structure factors and the angles \$\gamma\$, \$\nu\$ and \$\rho\$.
A file xxxxx.ips where xxxxx is a name selected by the user. This file will contain a list of orders:

hkm h, k, l . .

in which there is an "hkm" line for each reflection satisfying the given criteria.

Running the program:

On running the program the user is asked for the name of the crystal data file, the name for the output file (xxxxxn), and is asked to select the criteria to be used to choose reflections. For each choice there is a default value. Typing a "RETURN" at any point while entering the choices within a group causes the defaults to be used for the rest of the parameters in the group. Typing an "=" at any point selects the default (or previous) value for a particular parameter.
The selection phase of the program can be repeated several times with each run producing files containing reflections satisfying the currently selected criteria. I f the filename xxxxxm is chosen for the first output file, the output filename in the second run will be xxxxxm+1 and so on.

Calls:

ANGLD3 ASK FCALC FILNOM GETGEN INCREM INDFIX ISPABS NOPFIL PREFIN RDINTG RDREAL RDWORD SAID SETDC SETFC SETGEN SYMREF SYMUNI UPONE VCTMOD

Common blocks used:

/IOUNIT/ to use LPT ITI ITO

/NSYM/ to use NOP

/SCRACH/ to use NAMFIL

Data Collection and Reduction . . . . . . . Main Program

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SUBROUTINE ANGLD3(H,A,ABSENT)

Calls:

DEGREE GMPRD ORTHO UNIVEC

Called by:

GENREF

Common blocks used:

/DGEOM/ to use UM

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