Subject: Re: geometry optimization

From: "Dr. Stefan Dapprich" <[email-masked]>
Date: Mon, 01 Dec 1997 15:27:40 +0100

Yubo Fan wrote:
> I am doing geometry optimization of a big molecule. I think it is
> impossible for me to do these jobs for the whole molecule which contains
> over 40 C atoms, so I want to split it into several parts and calculate
> each of them respectively. Then I will put them together. Is this thought
> possible? If possible, could you please give me some advice or reference
> with the same kind of work.

The next Gaussian release will allow you to specify different levels of
theory for different parts of the molecule. You can perform geometry
optimizations as well as frequency calculations at the combined level.
The method is called ONIOM and its implementation will be described in
an upcoming paper. However, you might want to take a look at previous -
slightly different - incarnations of the method (called IMOMM and
IMOMO).
See, for example:
F. Maseras, K. Morokuma, J. Comput. Chem. 1995, 16, 1170.
S. Humbel, S. Sieber, K. Morokuma, J. Chem. Phys. 1996, 105, 1959.
M. Svensson, S. Humbel, R. D. J. Froese, T. Matsubara, S .Sieber, K.
Morokuma, J. Phys. Chem. 1996, 100, 19357.

Hope this helps,
Stefan

-- 

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Dr. Stefan Dapprich
Philipps-Universitaet Marburg, FB Chemie
Hans-Meerwein-Str.
D-35032 Marburg
Phone  +49-6421-28-5561
Fax    +49-6421-28-2189
Email  [email-masked]

"to be or nut^H^H -- sh^Gt, how do I delete.^?^? Oh No Oh NO^D^D -- How
do I get out of this thing anyway ^C^C^C Kill it ^Z^Z^Z (mumble mumble)
Bus error (core dumped)
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