Subject: symmetry and stationary points

From: "E. Lewars" <[email-masked]>
Date: Wed, 27 Apr 1994 12:41:47 -0400

Patrick Bultinck started a discussion about whether or not symmetry constraints
should be used in calculations.  When we do a geometry optimization we're
seeking a stationary point (which almost alwars means a relative minimum or
a transition state).  Since it's sound practice to characterize any stationary
point you have found by calculating its freqs, it is probably a good idea to
routinely impose symmetry (for esthetic reasons and to save time) and let the
number of imaginary vibrations tell you when to relax it to go from a transition
state to a minimum.  
Theresa Windus says "while the molece with symmetry may not be the global
minimum...it is certainly some sort of stationary point..."  Does anybody
know of a formal theorem that says non-C1 structures are always stationary
points, or some place where this is explicitly stated?  It's just that it
would be nice to see some sort of proof; it's not quite obvious that it 
MUST be so, altho' I do see that it looks reasonable.
Thanks.
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