Merged two doc files

fix wall/ees command :h3

fix wall/region/ees command :h3

[Syntax:]

    sigma = size factor for wall-particle interaction (distance units)

      sigma can be a variable (see below)

    cutoff = distance from wall at which wall-particle interaction is cut off (distance units) :pre

zero or more keyword/value pairs may be appended :l

keyword = {units} or {fld} :l

  {units} value = {lattice} or {box}

    {lattice} = the wall position is defined in lattice units

    {box} = the wall position is defined in simulation box units

  {fld} value = {yes} or {no}

    {yes} = invoke the wall constraint to be compatible with implicit FLD

    {no} = invoke the wall constraint in the normal way

  {pbc} value = {yes} or {no}

    {yes} = allow periodic boundary in a wall dimension

    {no} = require non-perioidic boundaries in any wall dimension :pre

:ule

fix ID group-ID wall/region/ees region-ID epsilon sigma cutoff :pre

ID, group-ID are documented in "fix"_fix.html command

wall/region = style name of this fix command

region-ID = region whose boundary will act as wall

epsilon = strength factor for wall-particle interaction (energy or energy/distance^2 units)

sigma = size factor for wall-particle interaction (distance units)

cutoff = distance from wall at which wall-particle interaction is cut off (distance units) :ul

[Examples:]

fix wallhi all wall/ees xlo -1.0 1.0 1.0 2.5 units box

fix wallhi all wall/ees xhi EDGE 1.0 1.0 2.5

fix wallhi all wall/ees v_wiggle 23.2 1.0 1.0 2.5

fix zwalls all wall/ees zlo 0.0 1.0 1.0 0.858 zhi 40.0 1.0 1.0 0.858 :pre

fix zwalls all wall/ees zlo 0.0 1.0 1.0 0.858 zhi 40.0 1.0 1.0 0.858 

fix ees_cube all wall/region/ees myCube 1.0 1.0 2.5 :pre

[Description:]

Bound the simulation domain on one or more of its faces with a flat

"Fix wall/ees" bounds the simulation domain on one or more of its faces with a flat

wall that interacts with the ellipsoidal atoms in the group by generating a force

on the atom in a direction perpendicular to the wall and a torque parallel with the wall.  The energy of

wall-particle interactions E is given by:

means you cannot start your simulation with particles touching the wall

position {coord} (r = sigma_n) or with particles penetrating the wall (0 =< r < sigma_n) or with particles on the wrong side of the

wall (r < 0). 

"fix wall/region/ees" treat the surface of the geometric region defined by the {region-ID}

as a bounding wall which interacts with nearby ellipsoidal particles according to

the EES potential introduced above.

Other details of this command is the same wiht "fix wall/region"_fix_wall_region.html command. 

One may also find and exapmle of using this code in USER/ees/ under examples/ directory. 

[Restrictions:] 

This fix is part of the USER-MISC package.  It is only enabled if LAMMPS