GLASSVIR

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To read a configuration file (.cfg) from a RMCA modelling (glass or other), then to create 3D VRML-1 files (.wrl) containing polyhedra for a selected atom pair, which can be examined further with a VRML viewer like VRweb or Live3D (see below). This program is better suited for materials with exclusive environments (oxides, fluorides ...).

For information on RMCA, see : http://www.studsvik.uu.se/rmc/rmchome.htm
Some Window 95 executables are available (RMCA, RANDOM, MOVEOUT, CRYSTAL and NOCHAOS)
For information on VRML as related to crystallography see : http://www.cristal.org/vrml/intvrml.html
Recommended viewers for the VRML-1 files are :

VRweb : a standalone viewer available at http://www.iicm.edu/vrweb
Live3D : the plug-in delivered with Nestcape 3 or 4

The glassvir.zip file contains

• glassvir.exe : the executable
• glassvir.txt : the present manual
• rmc1045.cfg : one test file

The program is executed either by a double click on glassvir.exe from the explorer or inside a DOS box opened in the directory containing it by typing "glassvir".

The configuration file (.cfg) to be examined should be in the same directory as the executable.

When the program is started, you will have to give responses to a few questions, like for the following rmc1045.cfg test file :

If you had choosen a smaller box, the dialog would be :

Then the DOS box is closed automatically at the end of calculations (if it was opened by a double click from the Windows Explorator).

Files (all ASCII) will be created in the same directory :

• po.wrl VRML file with polyhedral rendering
• wi.wrl VRML file with wireframe rendering
• glassvir.pov POVRAY file for the aficionados (not tested yet)
• *.imp Output giving the summary of neigbours for the selected atom pair

Content of the file rmc1045.imp :

-------------------------------------------------------------------------- 
Calculation of neighbours in rmc1045 

No. of atom types = 4

Minimum bond lengths = 0.00000000E+000 
Maximum bond lengths = 2.15000010 

Type 3 - Type 4 neighbours:

6 300 100.000

Average coordination 6.00
--------------------------- 
--------------------------------------------------------------------------

The test file corresponds to a fluoride glass with formulation NaPbFe₂F₉, with 150 Na and Pb atoms, 300 Fe atoms and 1350 F atoms, in this order in the rmc1045.cfg configuration file :

Atom type :   1   2   3   4 
              Na  Pb  Fe  F 

Thus there are 10 atom pairs which are classified as :

Atom pairs : 1     2     3     4     5     6     7     8     9    10
           Na-Na Na-Pb Na-Fe  Na-F Pb-Pb Pb-Fe  Pb-F Fe-Fe Fe-F   F-F 

So that if you want to observe the Fe coordination with fluorine atoms, you should select the ninth atom pair and this corresponds to the central and neighbouring atoms number 3 and 4. This should clarify the responses given to the questions asked above and recalled below :

which one do you want to select ? 9
which central and neighbouring atoms ? 3 4
Minimum and maximum bond lengths ? 0 2.15

These bond lenghts allow to find exclusively FeF₆ polyhedra in this particular case.

• Don't try to examine self atom pairs (1-1, 2-2, 3-3 etc), or try after all...
• The limit is 10000 atoms involved in polyhedra
  for instance 2000 AX₄ or 1000 AX₉ or 500 AX₁₉ ; if you want more, try to ask for it.
• AXn polyhedra are recognized for n = 3 to 20 included
  for n = 3, a triangle joining the X atoms is drawn
  for n > 3, a convex polyhedron, regarding the A central atom is drawn, in principle.
• This is a beta test version : call lebail@univ-lemans.fr but remember this is a freeware, no guarantee is proposed. You may also ask for the FORTRAN 77 source.
• Verify time to time if there is not a new version at : http://www.cristal.org/

• Colors have to be modified by hand (editing the .wrl files).
• Ball and stick rendering is not implemented yet.
• Perspective can be changed only by editing (you should know some VRML language...).