REFM90 : Convert SCFS-90 file to/from a BDF

Author: Howard Flack, Laboratoire de Cristallographie, University of Geneva, CH-1211 Geneve 4, Switzerland

REFM90 converts an XTAL archive bdf to an SCFS format file (SCFS-90, Brown, 1983, 1985, 1988, 1990) and a SCFS-90 file to an XTAL archive bdf.

Introduction

The Standard Crystallographic File Structure (Brown, 1983, 1985, 1988, 1990) is the current (July 1990) standard approved by the IUCr Data and Computing Commissions as the standard format for exchanging crystallographic data. REFM90 is a program for two-way conversion between an archive bdf and the SCFS-90 format.

A file of crystallographic data in a standard format has many potential uses. It should be a very convenient means of submitting short format papers for publication in Acta Cryst. C, for archiving crystallographic information, for transferring a series of measurements made on a single-crystal diffractometer, for transfer of data between computers in a multi-host environment, for running programmes external to an integrated system such as XTAL, for communicating crystallographic data between laboratories by way of e-mail, floppy disks or magnetic tapes or for the preparation of material for deposit in electronic or hard-copy form. In REFM90 data are exchanged between the two file formats without any checking of their integrity and without any change of their potential information content.

Much of the code of REFM90 is taken or inspired from the programs REF87 and REFORM. REFM90 adheres strictly to the SCFS-90 standard. Superseded SCFS sections can neither be read nor produced by REFM90. Also, in those parts of the SCFS-90 standard where there is an indicated recommendation or preference for one format of the data over another, ONLY the recommended or preferred form can be interpreted by REFM90. REF() does not treat or use the SCFS-90 sections designed for macromolecular crystallography.

Description

1. XTAL to SCFS Mode

The information of one single data set specified by its Data Set Number is output in SCFS-90 format. The data set to be output is selected on the REFM90 line. The SCFS-90 sections output are as follows: TITLE; CELL DIMENSIONS(CID's: CELL, ERRS, VOL, PHYS); SGNAME(CID: LATT); SYMMETRY(CID: SYOP); FORM FACTOR(CID: TABL); FORMULA(CID: FORL); CONDITIONS(CID's: INT, ABS, STAT); CRYSTAL(CID: SCAL); ATOMS(CID: ATCO, ATCE, UALL, UIJ, UIJE); either HKL PACKor HKLwith CID: FOBS, FSQR, INTor CALCaccording to the choice made on the REFM90 line.

2. SCFS to XTAL Mode

In reading an SCFS-90 file a completely new archive bdf is created. The same sections and CID's that can be produced in mode (1) can be interpreted in mode (2). This mode just dumps the data from the SCFS file into the archive bdf. It is essential to run STARTX immediately after REFM90 in SCFS to XTAL mode in order to check the integrity of the data and to assure that the archive bdf is completely formed.

File Assignments

  SCFS-to-XTAL XTAL-to-SCFS
Reads sfi archive bdf
Writes archive bdf scf

Examples

REFM90                     :Convert XTAL bdf to SCFS87 file

REFM90 SCFS              :Convert SCFS90 file to XTAL bdf

References

  • Brown, I.D.(1983). Acta Cryst. A39, 216-224.

  • Brown, I.D.(1985). Acta Cryst. A41, 399.

  • Brown, I.D.(1988). Acta Cryst. A44, 232.

  • Brown, I.D.(1990). Acta Cryst. A46, In press.