Subject: CRYSTAL 95

From: "Marek J. Smolinski" <[email-masked]>
Date: Wed, 10 Jun 1998 12:48:25 +0200 (MET DST)

Dear CCLers,

I had some troubles with the CRYSTAL 95 program.

In order to get the energy hypersurface of crystall compund
(for example MgSO4.H2O)
I have to displace atoms of water molecules in the primitive cell. 
I used the ATOMDISP, MODISYMM and KEEPSYMM/BREAKSYMM keywords.
I don't know exactly how Flags of MODISYMM work.

I have some questions.

1) I do not know how the KEEPSYMM/BREAKSYMM keywords work;
   especially, what is the relationship of these keywords
   with the MODISYMM keyword. Do the  KEEPSYMM/BREAKSYMM
   keywords "interact" somehow with the MODSISYMM keyword?
   (or in other words: does the MODISYMM keyword change
    the the meaning of KEEPSYMM/BREAKSYMM?)

2) Do the FLAGS of MODISYMM describe the symmetry relationship
   between two atoms ?

3) What are the acceptable values of these flags ?

4) What is the meaning of the sign of these flags (+ or -) ?

5) What does mean the flag=0 ?

Thanks in advance,

Marek Smolinski
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