Subject: Re: CCL:symmetry change

From: Wai-To Chan <[email-masked]>
Date: Fri, 6 Apr 2001 19:08:08 -0400 (EDT)

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The following simple job dies as stated. I am using G98W A.9.
Phillip has a H2O input file that also fails. I am curious if his also
completes a complete iteration after the symmetry change is detected
before crashing with x=2.

   I ran this job with an added keyword and got it completed with the
symmetry advantage apparently retained. Here is the input file:

--------------------------------------
# b3lyp/3-21g opt=verytight symmetry=loose

h2o freq

0 1
.....  z-matrix snipped ....

--------------------------------------
  I did not use exactly the unrestricted method as you did but the reason 
your job crashed was the slight distortion from the Cs symmetry. In your 
case the initial geometry in your is actually C1. It also happened 
to me that in the course of DFT geometry optimization distortion from
a Cs symmetry of the starting geometry to C1 could set in
and abort the job. To get around 
this follow these steps: 

	Lift the cartesian coordinates of the geometry from the last 
optimization step and edit it to a gaussian input format. 
Here are the coordinates taken from the aborted job starting
> from your original job input

1    -0.813997     0.000001    -1.864364
7    -0.764606     0.000001    -0.863704
6     0.024411     0.000000     0.037382
8     0.770027    -0.000001     0.971039

   You then zero all of the nearly-zero coordinates
in the middle column to force
the symmetry back to Cs from C1 and restart the job
with or without the 'symmetry=loose' option. The option may not work
for large distortion. 

Wai-To Chan