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fix wall/lj93 command

Syntax:

fix ID group-ID wall/lj93 style coord epsilon sigma cutoff 

Examples:

fix wallhi all wall/lj93 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 9-3 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 is derived by integrating over a 3d half-lattice of Lennard-Jones 12-6 particles.

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 command

Default: none