[gmx-users] Help about 2 D periodic boundary condition

David spoel at xray.bmc.uu.se
Mon Jan 13 21:15:23 CET 2003

On Mon, 2003-01-13 at 21:58, David L. Bostick wrote:
> > I have also played a bit with epsilon_surface in water simulations. If
> > you use the value you put in for epsilon_surface for computation of the
> > dielectric constant (g_dipoles -epsilonRF epsilon_surface) you get the
> > same dielectric constant in all cases. However the Debye relaxation time
> > (which happens to be roughly correct fo SPC/E with tin-foil BC) is
> > ruined by using epsilon_surface not infinity. This makes me a bit
> > suspicious... Or is there a correction for this too?
> Ok, that's difficult.  I don't believe I can answer that, but again, when
> you set epsilon_surface, it is for r->infinity from the central simulation
> cell.  It is difficult to say how different dielectric constants affect
> things.  The JCP I cited in the previous message about dielectric constant

I'm getting old... Paul van Maaren just pointed out to me that the
answer to my question is in a paper of ours from 1998
(JCP 108, 10220, 1998). Thanks for your comments anyway.

Groeten, David.
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 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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