[lammps-users] Fixing a surface

Hi friends,
           I am working with liquid Na drop and Ni surface with EAM
potential. I want to freeze the Ni surface on which I like to
keep the Na droplet. What should be the command for freezing
the surface so that during dynamics the surface will retain its
shape but interaction between surface and droplet will exist. I
want to see the wetting behaviour of liquid droplet on the
metal surface.

fix 1 surface setforce 0.0 0.0 0.0 -- will it be suitable command
for my case?

Abhiram Hens
MTech Student
Department of Chemical Engineering
IIT Kanpur

Hi friends,
I am working with liquid Na drop and Ni surface with EAM
potential. I want to freeze the Ni surface on which I like to
keep the Na droplet. What should be the command for freezing
the surface so that during dynamics the surface will retain its
shape but interaction between surface and droplet will exist. I

if you don't want to move the Ni surface, you don't need a potential
for their interactions, you only need a potential for the interactions
of the Na drop *with* the Ni.

i am not certain, whether not moving the Ni atoms is a good model,
though. even in a soild atoms do move and free surfaces reconstruct.,
if the Ni potentials cannot describe the free surface well, you could
use fix spring/self to restrain the Ni atoms to their positions. but again,
you'd have to know the surface reconstruction for the best model
and some estimate of the spring constant.

want to see the wetting behaviour of liquid droplet on the
metal surface.

this has been discussed many times on this list. please
search the mail list archives for answers already given,
before asking a common question.

fix 1 surface setforce 0.0 0.0 0.0 -- will it be suitable command
for my case?

in combination with setting the velocities to zero and
nve time or nvt time integration, yes.
you can also just not time integrate those Ni atoms.

cheers,
    axel.