[Fwd: Re: [gmx-users] calculating dielectric constant]

David van der Spoel spoel at xray.bmc.uu.se
Tue Nov 14 09:21:53 CET 2006

Hi David,

Yes, I run the mdrun at T=425K. I simulated the simplest ionic liquid
(mmimCl).  I don't find the reported dielectric constant of this one,
but I have some reported data of some other ionic liquid at hand,
epsilon~ 10 - 20.  Therefore, the data from gromacs is quite big.
(Should I provid the index.ndx with the molecular number? I don't think
so. But I am not sure about it. And I don't how to get the index.ndx
file with the molecular number.
http://www.gromacs.org/pipermail/gmx-developers/2003-December/000714.html )

For ionic liquids one expects the dielectric constant to be high. 10-20 
looks way too low.
Check convergence of the dielectric constant by looking at epsilon.xvg

David van der Spoel, PhD, Assoc. 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://folding.bmc.uu.se

More information about the gromacs.org_gmx-users mailing list