Liquid R152a molecules not evaporating

Dear all,

I am trying to simulate phase change of R152a refrigerant on a platinum surface. I have used the forcefield parameters given on the following literature, Redirecting
I am using Langevin thermostat to set the temperature of the platinum surface.
Even after setting the temperature of the surface at 500K which is far above the saturation temperature of the liquid there is no evaporation, and the liquid is behaving sort of like an amorphous solid.
I am not facing any errors while running the simulation and I can’t seem to figure out what i am doing wrong. I am attaching my input files and an animation of the system.

Any help would be much appreciated. Thank you.

Animation
data.lammps (1.3 MB)
parm.lammps (829 Bytes)
ref_evap.in (2.7 KB)

Have a look at the posts in this forum dealing with “phase change” and hysteresis effects. You should have got some suggestions while typing your post.

Nothing to worry about. There is plenty of explanations given by people much more expert than I am, so you better refer to these posts.

  • Your topology for the R152a molecules seems wrong. How did you create the data file?
  • Your platinum system is not commensurate with periodic boundary conditions.
  • Since you want to keep part of the platinum system mobile, why not use an EAM model for it and thus pair style hybrid overall?
  • Your box is extremely tall. Keep in mind that with kspace_modify slab 3.0 the box is enlarged by a factor or 3 in z direction. You may be wasting CPU resources. When running in parallel, you should be using processors * * 1 for the same reason

My suggestion is that you make some tests for each subsystem separately, i.e. do a simulation of a bulk platinum system at the target temperature and determine the effective lattice parameter for that.
Also, you should be running the refrigerant as a separate, small bulk system and verify the topology and force field.