Dialog Box: Import ICSD File [File menu or button in Startup or Control Window]
This imports files from the Inorganic Crystal Structure Database. Four types of ICSD file are supported, classified according to source:
1) Files from the current CD-ROM database, accessed by the program RETRIEVE. The RETRIEVE files must be written from the DATA window using the PRINT option, not as export files (if there is sufficient demand, export files may be supported). That is, the file should be a copy of what is shown on the screen in the RETRIEVE program.
2) Files from the Canadian Scientific Numeric Database System (CAN/SND). This service may no longer be available. The files are referred to as CRYSTIN, but are different from original 3) CRYSTIN files.
3) Original CRYSTIN files, available from the Netherlands CAOS information system, from ETH (Switzerland) and perhaps other sources.
4) Files from the the ICSD World Wide Web site (barns.ill.fr/dif/icsd/).
In CAN/SND files, VIBRATZ will use the "NA:" line for the title; in RETRIEVE and original CRYSTIN files, VIBRATZ will use the first "MINR" line if present, otherwise it will use the "NAME" line.
VIBRATZ distinguishes among the four different file types by reading part of the main title or "Collection" line, which gives the ICSD index number:
1) RETRIEVE - " COL Collection Code "
2) CANSND - "ID: "
3) ORIGINAL - " **** COLLECTION CODE COL= "
4) WWW - " COL ICSD Collection Code "
In each case the index number follows the above excerpt. Note that in all file types except CANSND there is always a blank character in the first column.
Please contact Shape Software if you have ICSD files which cannot be read by one of these options. The best procedure is to send samples of the files by email or on a floppy diskette.
If there is more than one data set in a file, the Data Sets...in Import File dialog will appear, and you can select the data set. Each line will show the sequence number in the file, the ICSD number, and the first 24 character of the title as selected above. A maximum of 50 data sets can be listed in each file.
Symmetry for RETRIEVE. The crystal symmetry can be taken from the SGR line, which has the space-group symbol -this will result in the Space-Group Symmetry option; or from SYM lines, each of which contains one equivalent position or symmetry operator in xyz notation - this will result in the Custom Symmetry option. For consistency it is best to use the symbol from the SGR line, but if this gives incorrect results because of a non-standard orientation, try selecting SYM lines. The symbol in the file has "S" added to the end for non-standard settings (i.e. origin not on a center of inversion), and in this case VIBRATZ automatically uses the equivalent positions, leaving the "S" on the end of the symbol. Thus manual selection of the equivalent-position option may seldom if ever be needed.
If there is more than one atom at a single position, only the first will be read in - occupancy factors are ignored.