I am fairly new to LAMMPS and am trying to “shoot” a hydrogen atom at an amorphous water-ice slab. The slab is comprised of 1000 water molecules, and I am simply trying to place an atom at some point above the slab, give it an initial velocity, and see if the hydrogen atom sticks to the slab.
I can create the slab fine, but I am having trouble assigning a velocity to a atom so that the atom will approach the slab. I have tried to explicitly set the velocity (i.e. with “velocity set” and assigning a value for vz), and while the printed velocity is the one I gave it, the atom will not move from its initial position.
I can fix the velocity to a certain value, this will move the atom but serves no purpose in what I’m trying to simulate because the velocity is staying fixed at that value. I just want an initial kick.
Of course, temperature scaling won’t do because this is a single atom. Temperature scaling (i.e. with “velocity create” or “velocity scale”) does work if I am using molecular hydrogen after I fix the bond as rigid between the two hydrogen atoms.
There must be something fundamental that I am doing wrong. Is there a way to do this in LAMMPS? Or is my approach just entirely incorrect. I’ve attached my input files.
I appreciate any and all help.
H_atom.in (946 Bytes)
H_atom.in.init (461 Bytes)
H_atom.in.settings (658 Bytes)