Subject: determination of geometry when a low barrier to rotation is present

From: Rudy Gostowski <[email-masked]>
Date: Mon, 06 Jul 1998 08:53:45 -0500

We are using GAMESS to determine the geometry of 9-aryl substituted
fluorenyl radicals.  When the aryl group is phenyl the barrier to rotation
appears to be small and the structure is uncertain.  Please suggest the
best way to find the true minimum for this molecule (unpaired electron on
carbon in parenthesis):

           ::C:
        C       C
         :        ::
        C       C
           ::C: 
              :
  ::C :  : (C) :  : C::
C      C        C       C
:        ::        ::       :
C      C    :   C       C
  ::C :             : C::

This needs to be accomplished at an ab intio level rather than
semi-empirical (MOPAC).
Your help with this is appreciated.

Rudy Gostowski
Department of Chemistry
Austin Peay State University
Box 4547
Clarksville, TN  37044
931-648-7624
FAX 931-648-5996
[email-masked]