Subject: One more Gaussian Front End Item

From: "Phil Hultin" <[email-masked]>
Date: Fri, 15 Mar 2002 11:03:45 -0600

Just an addition to the question of "front ends" for Gaussian.

Since G98 does all of its calculations in redundant internal coordinates, no
matter what input format the structure is in (unless instructed otherwise),
there is no need to construct Z-matrices at all.  ANY program that can
generate a file containing Cartesian coordinates from a drawn structure can
be used to create input files, along with a text editor to add the necessary
route commands etc.

I suppose there are specific cases where a Z-matrix is superior, especially
if you want to guide a geometry optimization in some ways, but you must
specify that the optimization be done in Z-matrix coordinates or G98 will
simply create redundant internals from your Z-matrix.  So, for most purposes
we just input Cartesians.

Of course, this approach still means you have to use the G98 input syntax
with all of its idiosyncrasies and inconsistencies - and those of you who
were reading CCL in the recent past know my opinions about that.  But it
does give you complete control, and is much cheaper than Gaussview (i.e.
basically free).

For a "back end" we have been using Molekel because it makes such lovely
pictures.

Dr. Philip G. Hultin
Associate Department Head and
Associate Professor of Chemistry
University of Manitoba
Winnipeg, MB, Canada R3T 2N2
(vox) 204-474-9814
(fax) 204-474-7608
mailto:[email-masked]
http://www.umanitoba.ca/chemistry/

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From: Lee Woodcock <[email-masked]>
Date: Fri, 15 Mar 2002 14:51:55 -0500 (EST)

Hi,

There is another good front end for linux users:

ghemical is a good (free) molecule buider that allows users to build rough
stuctures and clean them up with MM and Semi-empirical calculations. 

There is rpm and source available for download at the following website:

http://www.uku.fi/~thassine/ghemical/

good luck
Lee
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H. Lee Woodcock III              |   Phone: 706 542-7374
Ctr. for Comp. Quantum Chem.     |   Fax:   706 542-0406
University of Georgia            |   E-mail: [email-masked]
Athens, GA  30602-2556           |   http://zopyros.ccqc.uga.edu/~hlwood
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