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lammps/doc/pair_lj_expand.txt
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pair_lj_expand.txt
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"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)
:line
pair_style lj/expand command :h3
[Syntax:]
pair_style lj/expand cutoff :pre
cutoff = global cutoff for lj/expand interactions (distance units) :ul
[Examples:]
pair_style lj/expand 2.5
pair_coeff * * 1.0 1.0 0.5
pair_coeff 1 1 1.0 1.0 -0.2 2.0 :pre
[Description:]
Style {lj/expand} computes a LJ interaction with a distance shifted by
delta which can be useful when particles are of different sizes, since
it is different that using different sigma values in a standard LJ
formula:
:c,image(Eqs/pair_lj_expand.jpg)
Rc is the cutoff which does not include the delta distance. I.e. the
actual force cutoff is the sum of cutoff + delta.
The following coefficients must be defined for each pair of atoms
types via the "pair_coeff"_pair_coeff.html command as in the examples
above, or in the data file or restart files read by the
"read_data"_read_data.html or "read_restart"_read_restart.html
commands, or by mixing as described below:
epsilon (energy units)
sigma (distance units)
delta (distance units)
cutoff (distance units) :ul
The delta values can be positive or negative. The last coefficient is
optional. If not specified, the global LJ cutoff is used.
:line
[Mixing, shift, table, tail correction, per-atom energy/stress,
restart, rRESPA info]:
For atom type pairs I,J and I != J, the epsilon, sigma, and shift
coefficients and cutoff distance for this pair style can be mixed.
Shift is always mixed via an {arithmetic} rule. The other
coefficients are mixed according to the pair_modify mix value. The
default mix value is {geometric}. See the "pair_modify" command for
details.
This pair style supports the "pair_modify"_pair_modify.html shift
option for the energy of the pair interaction.
The "pair_modify"_pair_modify.html table option is not relevant
for this pair style.
This pair style supports the "pair_modify"_pair_modify.html tail
option for adding a long-range tail correction to the energy and
pressure of the pair interaction.
This pair style can calculate per-atom energy and stress, as used by
the "compute epair/atom"_compute_epair_atom.html, "compute
stress/atom"_compute_stress_atom.html, and "dump custom"_dump.html
commands.
This pair style writes its information to "binary restart
files"_restart.html, so pair_style and pair_coeff commands do not need
to be specified in an input script that reads a restart file.
This pair style can only be used via the {pair} keyword of the
"run_style respa"_run_style.html command. It does not support the
{inner}, {middle}, {outer} keywords of the "run_style
command"_run_style.html.
:line
[Restrictions:] none
[Related commands:]
"pair_coeff"_pair_coeff.html
[Default:] none
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