From owner-chemistry@ccl.net Thu Nov  4 02:58:01 2010
From: "Gkourmpis, Thomas Thomas.Gkourmpis::borealisgroup.com" <owner-chemistry!A!server.ccl.net>
To: CCL
Subject: CCL: Potential energy scan and Transition state
Message-Id: <-43067-101104025613-12829-nQ4x/dPAAMz9i77JT9yEYw!A!server.ccl.net>
X-Original-From: "Gkourmpis, Thomas" <Thomas.Gkourmpis!=!borealisgroup.com>
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Content-Type: text/plain;
	charset="us-ascii"
Date: Thu, 4 Nov 2010 07:56:00 +0100
MIME-Version: 1.0


Sent to CCL by: "Gkourmpis, Thomas" [Thomas.Gkourmpis!=!borealisgroup.com]
Henry Hi

First of all which software are you using? The problem with the transition state is that it requires specialised techniques (QST2,3 etc) to be evaluated and then you need to verify it via IRC. Therefore the initial structure that the energy scan will yield for you is not 100% sure that will be the TS you're looking for. My recommendation is to take things in stages.

First run a PES on your structure to get an initial idea of the TS structure.
Then use this structure and identify properly the transition state. After that run an IRC to check that the TS you have is the correct one.

Still if you want to perform an optimisation at each point during PES then you need to define your input Opt=ts to tell the software to look for a transition state instead of a minima.

I hope this helps

Thomas

-----Original Message-----
> From: owner-chemistry+thomas.gkourmpis==borealisgroup.com%a%ccl.net [mailto:owner-chemistry+thomas.gkourmpis==borealisgroup.com%a%ccl.net] On Behalf Of Henry Martinez hmartine^gmail.com
Sent: Thursday, November 04, 2010 4:16 AM
To: Gkourmpis, Thomas
Subject: CCL: Potential energy scan and Transition state


Sent to CCL by: "Henry  Martinez" [hmartine+*+gmail.com]
I would like to do a potential energy scan (PES) with a Transition State (TS) at the same time. I 
mean, when the scan gets to the correct distance where the transition state happens I would 
like it to be calculated. Is that possible? If so, how the input should looks like? Anybody could 
give me an example with a simple SN2 reaction? Thanks a lot for the help.http://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt