how to model liquid/solid interface

Hello LAMMPS community,

My goal is to simulate ice formation on aluminium surface; i’ve successfully set up an initial geometry as the attached figure.

when I try to fix the whole system with NPT ensemble, I got the error message:

Out of range atoms - cannot compute PPPM

I’ve check out and put the command “delay 0 every 1 check yes” in the input script but it doesn’t help. The pressure is still NaN.

here is my input script:

Screenshot from 2015-09-04 21:56:42.png