From owner-chemistry@ccl.net Thu Apr 21 00:31:00 2011 From: "Andreas Klamt klamt^cosmologic.de" To: CCL Subject: CCL:G: Vibrational analysis with implicit solvation Message-Id: <-44441-110420150818-30846-Lde0Ek0IJ9YKJN6fhRcipw**server.ccl.net> X-Original-From: Andreas Klamt Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Date: Wed, 20 Apr 2011 21:08:08 +0200 MIME-Version: 1.0 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 >> 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> > > -- 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 Klamt