CCL: Transition States
- From: CCL CCL <computationalchemist]-[gmail.com>
- Subject: CCL: Transition States
- Date: Thu, 3 Sep 2009 11:17:21 -0400
Dear Friends,
I am modelling a reaction pathway,
using different level of theory,
say AM1, HF/3-21G, HF/6-31G,
B3LYP/6-31G etc.,
When, i use the semi-empirical
approach, i could trace all the transition state species in the pathway.
But, when i use the geometry in higher level, say HF and in DFT (B3LYP), i
am not getting the
same TSs, as I got in semi-empirical
methods, but to the intermediates.
Does that mean
there is a change in the mechanism in the reaction, or it is just
the inability of the DFT to trace the species.
I
was suggested to do the single point calculationes for those species using
higher level
denoted as (AM1//B3LYP/6-31G) for such a
situation.
Could anyone please help me to point out some references,
where such situation has been used
reported in the literature, where
the single point calculationes at DFT and HF level are carried out
for the TSs obtained over the semi-empirical
approaches.
Best regards,
Dr.
Sanjay
--
Regards,
Dr. Sanjay Bharathwaj Kumar
Dharmendra Institute of Technology,
Nagapattinam.