Subject: Re: CCL:G:SPARTAN & Z-MATRICES

From: <[email-masked]>
Date: Wed, 27 Sep 1995 17:58:00 -0400

> I am using the Build option of SPARTAN (Version 4.0.2) to minimize 
> the energy of some medium sized clusters containing up to 40 atoms. 
> I would like to obtain the Z-matrix of the energy-minimized 
> structure in order to be able to use this Z-matrix as input for the 
> GAUSSIAN92 or any other ab initio program. Can SPARTAN return the 
> Z-matrix ? I will be very thankful for any help.

Sorry Stefan,

There isn't an easy way to generate a Z-matrix from Spartan but if you 
insist....  Spartan will generate Gaussian Cartessian input which you 
can do manually following the instructions given in:

     'Spartan_root'/help/Notes/Running_G92

You can cut-and-paste the XYZ coordinates from the Gaussian or Spartan 
input [WARNING!  the Spartan archive is, or was, in atomic units!] 
into a new file and use the Gaussian supplied utility 'newzmat' to 
generate a Z-matrix following information in the Gaussian manuals.  
Unfortunately, I find this procedure rarely, if ever, generates the 
kind of Z-matrix one would prefer.  If it doesn't you'll have to edit 
it by hand [WARNING!  Changing the atom order may cause severe 
difficulty when trying to reimport the Gaussian results into 
Spartan!].

If you are using Gaussian 94, you have a much easier alternative.  
Just use Cartessian coordinates along with the 'Add_Redundant' option 
to apply contraints, scan coordinates, or compute/update specific 
force constants.  Check the "Gaussian 94 User's Manual" and the 
release notes about the "Add_Redunant" option.

Hope this helps.

Karl
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| Karl F. Moschner, Ph. D.                                              | 
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