Dear
André, Thanks for your adviceI
Regards Gustavo
Gotelli Polymer Development
De:
owner-chemistry+ggotelli==kaliumtech.com(~)ccl.net
[mailto:owner-chemistry+ggotelli==kaliumtech.com(~)ccl.net] En nombre de
André Farias de Moura moura_-_ufscar.br Enviado el:
sábado, 21 de marzo de 2015 15:38 Para: Gotelli, Gustavo A
Asunto: CCL:G: Gaussian IR frequency
calculation not really a Gaussian issue, the frequencies from the standard
harmonic oscillator model need to be scaled. Scaling factor depend on your
choice of basis set and level of theory, so you need to find out if anybody has
ever published a scaling factor for your specific choices (rb3lyp/6-311++g(d,p)), otherwise you have to obtain the
proper factor by yourself. for the unrestricted case, take a look
at: J.
Phys. Chem. A, 2005, 109 (12),
pp 2937–2941, for instance. On Sat, Mar 21,
2015 at 12:46 PM, Gustavo A Gotelli ggotelli*|*kaliumtech.com <owner-chemistry|,|ccl.net> wrote: Sent to CCL by: "Gustavo A
Gotelli" [ggotelli- -kaliumtech.com] Hi all!
I'm using G03W for doing
an IR frequency calculation using the 6-311g basis set, # opt freq
rb3lyp/6-311++g(d,p) pop=savemixed geom=connectivity scf=tight
The
problem is that results are far from experimental data, with differences
around 300/400 cm-1 between calculated and experimental peaks. I guess is
because I'm using wrong parameters, perhaps the basis set. Can somebody
suggest how to get results that better fits experimental data?
Thanks in
advance Gustavo
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--
_____________
Prof. Dr. André
Farias de Moura Department of Chemistry Federal University of São
Carlos São Carlos - Brazil phone:
+55-16-3351-8090 |