From chemistry-request@server.ccl.net  Wed Nov 10 18:28:56 1999
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Date: Wed, 10 Nov 1999 15:18:35 -0800
To: Yunfeng Hu <yunfeng@chem.ucla.edu>
From: David Gallagher <dgallagher@fujitsu.com>
Subject: Re: about precomplex
Cc: chemistry@ccl.net
In-Reply-To: <Pine.GSO.3.95.991110133456.19005B-100000@neon.chem.ucla.ed
 u>
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If you are using MOPAC, first check you have a true transition state by
running a FORCE calculation which should show one and only one negative
vibration. Then run the IRC=1 and IRC=-1 calculations to find the reactants
and products (minima) on either side of the transition state. One of these
may lead to the precomplex or intermediate that you suspect.

Regards,

David Gallagher, Fujitsu CCS.

At 01:44 PM 11/10/99 -0800, Yunfeng Hu wrote:
>Hi,everyone
>Recently I'm doing some ion reaction and dipolar cycloaddition
>calculation. I found in both cases that the energy of reactants(simple 
>energy sum of each reactant faraway) is larger than that of TS in gas
>phase. Can someone tell me how to find the precomplex in an unexpensive
>way? 
>Thanks in advance.
>
>Yunfeng

>
>
>