Subject: OPT=TS....FREQ....IRC

From: "C.M.Windsor" <[email-masked]>
Date: Thu, 18 Jul 1996 09:51:01 BST

I am reposting this due to an error sending a previous version (sorry 
for wasted bandwith) 
  
I am using G94 to perform TS calculations using the methods 
employed by Kendall Houk et al (Modelling of Diels-Alder TS) where by 
LST was used for the initial guess, OPT=TS for the optimisation to 
TS, FREQ to confirm it is a real TS and then an IRQ search around the 
reaction trajectory.  I would like to know the purpose of the FREQ 
calculation other than to calculate the ZPE and check for presence of 
single -ve eigenvalue (already shown in OPT=TS calculation).
Am I missing something that I should be checking?

Thanks in advance.
Carl
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 From Carl Mark Windsor University of Manchester Institute
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