[gmx-users] free energy contributions

David van der Spoel spoel at xray.bmc.uu.se
Fri Jan 30 11:46:01 CET 2004

On Fri, 2004-01-30 at 11:30, Michael Brunsteiner wrote:
> dear gmx-users,
> Is there a way to obtain the VdW and electrostatic
> contributions to the free energy ?
> I understand that the value given in the dgdl.xvg file
> for dU/dlambda is the derivative of the full potential energy 
> (sum of VdW and electrost.) with respect to lambda.
> I'd like to know both dU_el/dlambda and dU_vdw/dlambda ...
> cheers,
> Michael
not without programming. in the innerloops it is not computed
separately. Most of us have been trained by puritans (read Berendsen and
Van Gunsteren) who say that it is not physically meaningful to decompose
the free energy in different terms, *unless* you can rigorously prove
that the components are independent of the path...

David van der Spoel, PhD, Assist. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,  	75124 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://xray.bmc.uu.se/~spoel

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