Subject: SUMMARY: Mopac 7.0 and symmetry

From: [email-masked] (Joachim Schulte)
Date: Wed, 9 Aug 1995 13:43:44 +0200 (CST)

Dear Ladies and Gentlemen, 

my problem was that Mopac 7.0 did not recognize some point groups 
correctly, namely IH and D5H. 

Dr. James Stewart and Dave Close both recommended to switch
to MOPAC 93 for doing routine calculations. MOPAC 7.0 indeed 
has  problems  recognizing the point groups of many systems.

Dr. Stewart writes:

''MOPAC 7 was not designed to recognize C60.  MOPAC 7 was limited 
 to systems for which the principal axis is either perpendiculer
 to a set of atoms (Benzene) or goes through some of the atoms.   
 In C60, the principal axis is through the middle of a pentagon.  

 For routine use, MOPAC 93 is recommended over MOPAC 7.  MOPAC 93
 will recognize C60 as being Ih, and a whole slew of weird and
 wonderful systems - truncated icosahedra (like C60), truncated
 cubes and tetrahedra, and `twisted' icosahedra (point-group `I')...''

So I will switch to MOPAC 93 for my calcluations on fullerene systems. 

Many thanks to Dave Close and Dr. Stewart. 

Sincerely Yours, 

Joachim Schulte