Some questions about atom velocity and position


I'm a new learner of MD simulation, and recently I want to simulate an ion implantation process to bulk silicon substrates, and obtain the ion's penetration depth.

I have a question about LAMMPS input file coding.

I set the initial position of the ion by "create_atoms" command
and set the velocity of ion by "variable" command,
and "velocity" command, as described below.

------------LAMMPS code--------------
units metal
create_atoms 2 single \{ionx\} {iony} ${ionz} units box #(0,0,5)
mass 2 4.0 #helium-ion
group group_ion type 2
timestep 0.001

velocity group_ion set 0.0 0.0 $v0 unit box
thermo 10

dump dump_custom group_ion custom 10 dump_ion.atom id x y z vx vy vz fx fy fz

Are you time integrating the atoms with something like fix nve?