[gmx-users] spherical box

David spoel at xray.bmc.uu.se
Thu Jun 5 13:53:00 CEST 2003

On Thu, 2003-06-05 at 11:12, Anton Feenstra wrote:
> Erik Lindahl wrote:
> > Hi,
> > 
> > No, that's a physical impossibility since there is no crystal class with 
> > spherical symmetry.
> > 
> > Perhaps you're thinking of 'droplet' boundary conditions, but they are 
> > really falling out of popularity compared to accurate Ewald summation in 
> > periodic boxes. We've never bothered to implement it for that reason, 
> > and I doubt we will in the future (it's not difficult for somebody else 
> > to do, though).
> Using a combination of genbox or genconv, and trjorder it is already quite
> easy to generate a 'drop' of water. Turning off pbc is also trivial, but
> there is no straightforward feature to keep water from evaporating into
> the vacuum. There are also terrible artifacts involved with the water
> surface, related to dielectric properties and surface tention.

actually it is still used quite a lot, and new algorithms are being
developed to deal with it. I'll check the reference...
> Is there any specific reason why you need this type of system set-up?
Groeten, David.
Dr. David van der Spoel, 	Dept. of Cell and Molecular Biology
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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