Syntax:
fix ID group-ID spring/self K
Examples:
fix tether boundary-atoms spring/self 10.0
Description:
Apply a spring force independently to each atom in the group to tether it to its initial position. The initial position for each atom is its location at the time the fix command was issued. At each timestep, the magnitude of the force on each atom is -Kr, where r is the displacement of the atom from its current position to its initial position.
Restart, fix_modify, thermo output, run start/stop, minimize info:
This fix writes the original coordinates of tethered atoms to binary restart files, so that the spring effect will be the same in a restarted simulation. See the read_restart command for info on how to re-specify a fix in an input script that reads a restart file, so that the operation of the fix continues in an uninterrupted fashion.
None of the fix_modify options are relevant to this fix. No quantities calculated by this fix can be output by the thermo_style custom command. No parameter of this fix can be used with the start/stop keywords of the run command. This fix is not invoked during energy minimization.
Restrictions: none
Related commands:
Default: none