move

This keyword is used to move part of the system with a constant velocity.

Syntax

The move keyword requires 4 parameters:

move <moving_group_id> <velocity_x> <velocity_y> <velocity_z>

Here, moving_group_id specifies the group id for the moving part, which should be defined in the grouping method 0. The next three parameters specify the moving velocity vector, in units of Ångstrom/fs.

Example

One can first equilibrate the system and then move one group of atoms and at the same time fix another group of atoms:

# equilibration stage
ensemble npt_scr 300 300 100 0 0 0 100 100 100 1000
run 1000000

# production stage
ensemble nvt_scr 300 300 100
fix  0            # fix atoms in group 0
move 1 0.001 0 0  # move atoms in group 1, with a speed of 0.001 Ångstrom/fs in the x direction
run  1000000

Caveats

  • One cannot use NPT when using this keyword.

  • Currently, the moving group must be defined in the grouping method 0. This might be extended in a future version.