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What is the way then to calculate free energy in solution (including entropy contribution of a solute etc)?

Tatiana Alieva
vishnevoe00@list.ru


Dear Alex,
If eq. 4 from Klamt and colleagues is arguable, what is an alternative way to calculate free energy in solution (with entropy contribution of a solute etc…)?
In the discussion you mentioned in your answer, you proposed to compare electronic energies, but for comparison of a calculation with experimentally observable values (at least with a distribution between different states in the solution) one needs to take into consideration entropy contributions too.

I really do appreciate your comments!
Tatiana

On Sat Mar 15 '14 6:21pm, Alex Granovsky wrote
----------------------------------------------
>Dear Tatiana,

>> Is it the case for Firefly too? So that to get the solution-phase
>> free energy the thermal correction to the free energy of the solute
>> in the gas has to be added to Firefly's TOTAL FREE ENERGY IN
>> SOLVENT?

>You are right in that the "total free energy" is used mainly due to
>historical reasons. Be careful here though as explained in this thread:

>http://classic.chem.msu.su/cgi-bin/ceilidh.exe/gran/gamess/forum/?C35e9ea902bHW-8817-20+00.htmhttp://classic.chem.msu.su/cgi-bin/ceilidh.exe/gran/gamess/forum/?C35e9ea902bHW-8817-20+00.htm
>
>
>As to Eq. 4, note not everybody agree with Klamt. For instance,
>my view is that their  Eq. 4. is not correct either and that the
>following:

>> "any noncanceling differences in the thermal contributions in the
>> two phases (e.g., entropic changes associated with structural
>> reorganization of the solvent)are indirectly incorporated into
>> (Esoln + Gnes) through parametrization of eq 3 to reproduce
>> experimental solvation free energie".

>is just a speculation, especially for D-PCM.

>Kind regards,
>Alex Granovsky


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