Sent to CCL by: Andreas Klamt [klamt ~ cosmologic.de]
Hi Arne,
I do not have Gaussian and know little about the latest version. Anyway, I think
the basic concept is unchanged: The calculated solvation energies do already
approximately and implicitly include the contribution arising from the
vibrational changes from gasphase to liquid phase. Hence the way to get the
correct total free energy would be to do a gasphase vibr. analysis combined with
a calculation of the solvation energy, which gives the difference between the
total free energy in the gasphase and liquid phase (as far as dielectric
continuum solvation models can do that).
Obviously you get a change if you calculate frequencies in solution. But the
result will be inconsistent. Whether Gaussian warns about that inconsistency I
do not know. In addition, in general (as I mentioned eralier) frequencies in
solution do not have such a simple connection to free energy as in the gasphase.
Regards
Andreas
Am 20.04.2011 18:01, schrieb Arne Dieckmann adieckma,googlemail.com:
Sent to CCL by: "Arne Dieckmann" [adieckma#,#googlemail.com]
Hi Andreas,
thanks for your answer. I can understand the points you are making in that J
Phys Chem A paper. However, I still don't know which contributions are included
in the free energy Gaussian calls "Sum of electronic and thermal Free
Energies". It has a different values when performing the frequency
calculation in the gas phase or in solution, so I guess some implicit solvent
contribution must be factored in, right?
Cheers,
Arne
On Apr 20, 2011, at 3:22 PM, Andreas Klamt klamt||cosmologic.de wrote:
Sent to CCL by: Andreas Klamt [klamt(_)cosmologic.de]
Dear Arne,
this issue is quite confusing. I have already commented a few times on this
issue in the CCL. I do not want to repeat that here.
An analysis is also given in
J Phys Chem A. 2010 Dec 30;114(51):13442-4. Epub 2010 Dec 6.
Comment on the correct use of continuum solvent models.
Hope this helps.
Andreas
Am 20.04.2011 13:43, schrieb Arne Dieckmann adieckma++googlemail.com:
Sent to CCL by: "Arne Dieckmann" [adieckma_-_googlemail.com]
Dear all,
I am performing a vibrational analysis in Gaussian03 using the M05-2X functional
and implicit solvation. The way I see the results is that the effect of
solvation is already included in in the free energy ("Sum of electronic and
thermal Free Energies="). Is that correct or do I need to apply the
correction for free energy to the "total free energy in solution"
(that's what it's called in the Gaussian output) estimated by the variational
PCM calculation?
Cheers,
Arne>
--
PD. Dr. Andreas Klamt
CEO / Geschäftsführer
COSMOlogic GmbH& Co. KG
Burscheider Strasse 515
D-51381 Leverkusen, Germany
phone +49-2171-731681
fax +49-2171-731689
e-mail klamt\a/cosmologic.de
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HRA 20653 Amtsgericht Koeln, GF: Dr. Andreas Klamt
Komplementaer: COSMOlogic Verwaltungs GmbH
HRB 49501 Amtsgericht Koeln, GF: Dr. Andreas Klamthttp://www.ccl.net/chemistry/sub_unsub.shtml>;
--
PD. Dr. Andreas Klamt
CEO / Geschäftsführer
COSMOlogic GmbH& Co. KG
Burscheider Strasse 515
D-51381 Leverkusen, Germany
phone +49-2171-731681
fax +49-2171-731689
e-mail klamt() cosmologic.de
web www.cosmologic.de
HRA 20653 Amtsgericht Koeln, GF: Dr. Andreas Klamt
Komplementaer: COSMOlogic Verwaltungs GmbH
HRB 49501 Amtsgericht Koeln, GF: Dr. Andreas Klamthttp://www.ccl.net/chemistry/sub_unsub.shtml>;