Subject: "Geometry is not a stationary point" message...

From: "Victor M. Rosas Garcia" <[email-masked]>
Date: Thu, 14 Mar 1996 12:13:35 -0500

Hi everybody,
	I currently running some geometry optimizations of some
phosphorus-containing rings in MOPAC93.  My route card looks like this:

PM3 GNORM=0.01 EPS=78.3 CHARGE=1 T=3600.00 EF LET DDMIN=0.0 NOINTER NOLOG

and in several cases I get the error message:

WARNING -- GEOMETRY IS NOT AT A STATIONARY POINT

In the manual says that:
"To avoid this message, make sure that the geometry can be optimized, given the
optimization flags you have chosen.  In particular, if (3N-6) optimization
flags are set, and there are no dummy atoms, then it is unlikely that this
message will be generated."

I guess I hit one of those *unlikely* cases  :(

So my questions are:
a) Do I have to worry about this message?
b) Should I reoptimize those geometries to get rid of the error?
c) Is it only an artifact because I specified a GNORM=0.01?  I'm wondering,
because in all cases the final gradient norm is < 1.0 and in most cases is <
0.5 (which I think is pretty good)

Any suggestions are welcome.

TIA

Victor

-- 
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Victor M. Rosas Garcia                   * "How can we contrive to be 
[email-masked]                *  at once astonished at the  
Virginia Tech doesn't necessarily share  *  world and yet at home in it?"
the opinions you just read.	         *  G. K. Chesterton
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