From owner-chemistry@ccl.net Fri Apr 29 04:26:00 2011
From: "servaas servaas.michielssens**student.kuleuven.be" <owner-chemistry^^^server.ccl.net>
To: CCL
Subject: CCL:G: implicit solvation
Message-Id: <-44485-110429040837-22776-MsOiA3Obgl/yckXlheV42w^^^server.ccl.net>
X-Original-From: servaas <servaas.michielssens * student.kuleuven.be>
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Date: Fri, 29 Apr 2011 10:08:07 +0200
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Sent to CCL by: servaas [servaas.michielssens[*]student.kuleuven.be]
According to the procedure described in Comment on the correct use of
continuum solvent models (J. Phys. Chem. A 2010, 114, 13442-13444). One
should proceed as follows using gaussian 09:
1. Optimize structure in vacuum and do frequency analysis, from this one
can find the free energy correction in the gas phase (dGcorr_gas)
2.Optimize the structure in solvent if you are using another solvent
model than SMD I think you should add the keyword cav, dis and rep. The
energy you get includes all corrections, also the non electrostatic
ones. So this it is actually E_solv + Gnes from the above paper.
3. So to find the free energy in solvent one can simply add everything:
dGcorr_gas + E_solv + Gnes.


I hope that helps,

Servaas

On Thu, 2011-04-28 at 19:53 +0200, Arne Dieckmann
adieckma[#]googlemail.com wrote:
> Sent to CCL by: Arne Dieckmann [adieckma ~ googlemail.com]
> Dear Dave,
> 
> I am aware of that. However, as I understand it frequency calculations should be done in vacuum as the equations are derived from an ideal gas assumption.

>  Am I wrong here? And what would be the energy I need to use from the PCM calculation? 
> 
> Cheers,
> Arne
> 
> On Apr 28, 2011, at 17:01, "Close, David M. CLOSED^mail.etsu.edu" <owner-chemistry/./ccl.net> wrote:
> 
> > 
> > Sent to CCL by: "Close, David M." [CLOSED++mail.etsu.edu]
> > Arne:
> >  You need to do a frequency calculation and then you will have all the thermodynamic parameters including the free energy, the zero-point energy, etc.
> >  Regards, Dave Close
> > 
> > -----Original Message-----
> >> From: owner-chemistry+closed==etsu.edu(!)ccl.net [mailto:owner-chemistry+closed==etsu.edu(!)ccl.net] On Behalf Of Arne Dieckmann adieckma]_[googlemail.com
> > Sent: Thursday, April 28, 2011 8:53 AM
> > To: Close, David M.
> > Subject: CCL:G: implicit solvation
> > 
> > 
> > Sent to CCL by: "Arne Dieckmann" [adieckma---googlemail.com]
> > Dear all, 
> > 
> > I am performing Gaussian calculations using implicit solvation (CPCM). Afterwards, I would like to apply thermal corrections from gas phase calculations to obtain free energy differences of certain molecules. The Gaussian output contains several energy values when using implicit solvation, e.g. "After PCM corrections, the SCF energy is  -193.093761350" and "Total free energy in solution with all non electrostatic terms". Which one would I use to add the correction for free energy? 
> > 
> > 
> > Thanks in advance, 
> > Arnehttp://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt> 
>