CCL: Potential energy scan and Transition state

 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