Short introduction for POWDER CELL 1.8b!
_________________________________________


POWDER CELL is a program for representation of crystal structures 
and calculation of the corresponding powder pattern. If you do 
not understand the manual existing unfortunately only in German and written in
LaTeX here are the most important remarks for the basic handling of POWDER 
CELL. 

For application the following files are nessecary:

pc.exe				executing file
pcemul.exe                      executing file for CPU's without FPU
pc.bld				structure image 
pc.cfg				configuration file
pc.dat				data file for space group generation
asfpc.dat			values for calculation of atom 	
				scattering factors
pcaac.dat                       atomic absorption coefficients 
pcrad.dat			radii of atoms and ions
pcwpg.cfg                       configuration file for WPG output
rtm.exe				runtime manager
dpmi16bi.ovl			dpmi server
egavga.bgi			graphic interface driver
*.cel				parameter files
pc.dvi                   Manual in LaTEX

At first copy the compressed File pc.zip and pkunzip.exe from the floppy disc 
to a certain directory on your hard disc drive. The name of this directory 
is of your own free choice, for instance C:\PC. Now decompress the zipped 
file by using the following command:

pkunzip pc.zip

More easy is the use of Norton Commander to decompress the zipped file.

POWDER CELL is compiled under Borland Pascal (7.0) and runs in protected mode. 
That means, that the whole memory is used. As minimum you need 
2 MB or better 4 MB of main memory. We tested the program only 
on computers  with a minimum of 4 MB. So it is possible that 
you get trouble by running POWDER CELL on a  computer of less 
than this equipment. As a minimum configuration we advise a PC 
with a 386 or 486 CPU. 
If a runtime error should occure and the program terminates you 
do not see this at any time, because the program do not switch 
in text mode. Only the frame of the screen is broken on the 
above left corner and no reaction on input is shown. In 
practice you should reboot the computer, because the dynamic 
variables of the program freeze the whole memory for further 
operations. But we hope that this case do not occure or is very 
rare.
The program disc contains some examples for input files. The 
input data can be written unformatted. Only the periodic number 
must set behind the 4th column. Line spaces are not 
alowed, only in a comment part after the last value for RGNR. 
In most of our examples containing on the program disc site 
occupation factors and isotropic temperature factors are not 
included. These two values must be given after the three 
coordinates, at first the site occupation factor and than the 
temperature factor. 

Example:

CELL       5.0   5.0   5.0    90   90   90
O       8      0.0         0.0       0.0         0.5       0.4
N       7      0.5         0.5       0.5         1         0.3       
H       1      0.333       0.333     0.333
RGNR   14

If you want applicate only the temperature factor the 
occupation factor is set to be 1. By substitution of one atom 
by another, for instance for 50%, you must set the site 
occupation factor as follows:

CELL       5.0   5.0   5.0    90   90   90
O       8      0.0         0.0       0.0         0.5       0.4
       16                                        0.5       0.45
N       7      0.5         0.5       0.5         1         0.3       
H       1      0.333     0.333    0.333
RGNR   14

In this example the Oxygene is at half substituted by a Sulfur  
atom (atomic number 16). The program checks the first four 
characters of the line. When these are empty, the program knows 
that this is a substitution. It follows only the atomic number 
and the occupation factor. The last value is the isotropic temperature factor. 
The keyword RGNR is the german word for "space group number" 
(Raumgruppen-Nummer), which are the same as defined in the 
International Tables of Crystallography (IT) from 1973. 
After the space group number a number for the cell choice (for 
instance 2 or 3) can follow, if existing in the file pc.dat (l. 
IT).
The keywords for the atoms can contain up to four characters. 
If the name is longer a runtime error occures.

If you have some problems with the program don't hazitate to contact us



         Werner Kraus                   Gert Nolze
    Federal Institute for Materials Research and Testing
          Lab. I.33                      Lab V.14
      Rudower Chaussee 5            Unter den Eichen 87
         12489 Berlin                   12205 Berlin

     Tel. (030) 6392 5845           Tel. (030) 8104 3109
     Fax: (030) 6392 5787           Fax: (030) 8112 029 

e-mail:   kraus@ah.bam-berlin.de
          gert.nolze@bam-berlin.de