Syntax:
fix ID group-ID wall/lj126 style coord epsilon sigma cutoff
Examples:
fix wallhi all wall/lj126 xhi 10.0 1.0 1.0 1.12
Description:
Bound the simulation domain with a Lennard-Jones wall that encloses the atoms. The energy E of a wall-particle interactions is given by the 12-6 potential
where r is the distance from the particle to the wall coord, and epsilon and sigma are the usual LJ parameters. Rc is the cutoff value specified in the command. This interaction provides a harder, more repulsive interaction with the wall than the softer 9-3 potential provided by the fix wall/lj93 command.
The wall potential is shifted so that the energy of a wall-particle interaction is 0.0 at the cutoff distance.
This fix supports the fix_modify options for thermo and energy. The former will print the contribution the fix makes to the energy of the system when thermodynamics is printed, where the energy of each particle comes from the integrated form of the equation above. The latter will add this contribution to the total potential energy (PotEng).
The forces due to this fix are also imposed during an energy minimization, invoked by the minimize command. If you want that energy to be included in the total potential energy of the system (the quantity being minimized), you must enable the fix_modify energy option for this fix.
Restrictions: none
Related commands:
fix wall/reflect, fix wall/lj93
Default: none