Hello lammps users
im trying to calculate a water contact angle of a water droplet on graphene.
for this im using cylinder bins “compute densidad_bins all chunk/atom bin/cylinder z lower 0.25 100.0 100.0 5.499 42.6 60 bound z 3.0 60.0 compress no units box” , where 100.0 100.0 is the initial center of mass of my droplet. But in the running section, I use NVT, later an NVE ensemble and with this, the center of mass of the droplet moves, so I tried to change the “… 100.0 100.0 …” for a c_COM c_COM , wich correspond to the X,Y position of the center of mass of the water group. But lammps send me an error “invalid compute command” because c_COM is not a floating number, but it is. So, how can i do to compute my bins always centered with the center of mass of the water droplet.
Of course then I use a fix command “fix densidad all ave/chunk 100 5 2000 densidad_bins density/mass ave running overwrite file dens_profile.lammpstrj”