[gmx-users] Lambda Dependence when delta_lambda = 0

[Ilya Chorny]

I read that in the manual but that make sense if you incriment lambda. What
happens if delta_lambda = 0.
Am I correct to say dh/dl = dH if delta_lambda = 0.

Ilya



-----Original Message-----
From: gmx-users-admin at gromacs.org [mailto:gmx-users-admin at gromacs.org]On
Behalf Of David
Sent: Wednesday, September 10, 2003 11:34 PM
To: gmx-users at gromacs.org
Subject: Re: [gmx-users] Lambda Dependence when delta_lambda = 0


On Thu, 2003-09-11 at 00:53, Ilya Chorny wrote:
> Hi Erik,
>
> I ran a short test trajectory where 100 ps calculating the free energy
> of going from Ar - LJ1 (argon with a sigma one Angstrom smaller). In the
> mdp file I set free energy to yes and kept the rest of the free energy
> parameters as defaults. I'm not sure I understand what the dH/dl in the
> case when delta_lambda = 0. Should it not just be the difference in the
> Hamiltonians between Ar and LJ1. The numbers seem a little high (~7000
> kJ/mol) and I would expect them to be negative.
>

dH/dl is the derivative of the energy with respect to lambda, it may
very well be non zero for any value of lambda. I think it is described
in the manual..

> Thanks,
>
> Ilya
>
>
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--
Groeten, David.
________________________________________________________________________
Dr. David van der Spoel, 	Dept. of Cell and Molecular Biology
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