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Re: [lammps-users] TIP5P support/development?
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Re: [lammps-users] TIP5P support/development?


From: "Ahmed E. Ismail" <aeismail@...24...>
Date: Sun, 29 Apr 2018 18:40:47 +0000

On Sat, Apr 28, 2018 at 9:01 PM Axel Kohlmeyer <akohlmey@...24...> wrote:
On Sat, Apr 28, 2018 at 7:42 PM, Ahmed E. Ismail <aeismail@...24...> wrote:
> Dear all:
>
> I know it was asked in an earlier post about TIP5P, but I was curious if
> anyone was currently working on trying to implement a five-point model in
> LAMMPS right now. One of my students is interested in working with TIP5P, so
> it would be good to know if anybody is currently developing such a model, or
> if there is sufficient interest to be worth doing it ourselves.

you can easily set up TIP5P using fix rigid/small. either disable the
test for per type mass == 0 or use something small like 1.0e-10.
only downside is the rather short time step required to have stable
time integration with rigid bodies.

I guess the big question here is how small does that time step need to be? With TIPxP styles, we can use SHAKE to get away with a 2 fs time step. I'd rather not have to do 20 or 30 time steps to replace that; I doubt that would be very efficient in the long run.

—AEI
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Ahmed E. Ismail
aei@...495...
aei@...496...