Re: [AMBER] What is the Value of C° (standard concentration) in calculating Free Energy

From: Adrian Roitberg <>
Date: Tue, 21 Dec 2010 08:57:20 +0100

Dear Sunita

This is a slightly tricky question, but in general it has a defined
answer. C° is usually defined as 1 M (in the case of biochemistry, the
std concentration of protons is 10^-7).

Look at some of Mike Gilson papers on this subject, and a recent very
nice paper in jctc

A Note on the Standard State’s Binding Free Energy
Ignacio J. General
J. Chem. Theory Comput., 2010, 6 (8), pp 2520–2524

On 12/21/10 7:56 AM, sunita gupta wrote:
> Hello Everyone
> After going through many articles on free energy calculation, I came across
> a term called "ACorrection" which need to be calculated for accurate value.
> Acorrection= -RT ln(C°V) = -RT ln [C°(2 pi RT/k)3/2]. Can anyone tell me
> what will be the value of C° (standard concentration), if Force constant(k)
> is in kcal mol−1Å2, Temperature is in Kelivn and R(gas constant) is 1.985
> cal<> K−1 mol−1.
> Many Thanks

                            Dr. Adrian E. Roitberg
                              Associate Professor
                Quantum Theory Project, Department of Chemistry
                            University of Florida
   Senior Editor. Journal of Physical Chemistry.
on Sabbatical in Barcelona until August 2011.
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Received on Tue Dec 21 2010 - 00:00:04 PST
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