lammps/doc/pair_brownian.txt

"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 brownian command :h3
pair_style brownian/omp command :h3
pair_style brownian/poly command :h3
pair_style brownian/poly/omp command :h3

[Syntax:]

pair_style style mu flaglog flagfld cutinner cutoff t_target seed flagHI flagVF :pre

style = {brownian} or {brownian/poly}
mu = dynamic viscosity (dynamic viscosity units)
flaglog = 0/1 log terms in the lubrication approximation on/off
flagfld = 0/1 to include/exclude Fast Lubrication Dynamics effects
cutinner = inner cutoff distance (distance units)
cutoff = outer cutoff for interactions (distance units)
t_target = target temp of the system (temperature units)
seed = seed for the random number generator (positive integer)
flagHI (optional) = 0/1 to include/exclude 1/r hydrodynamic interactions
flagVF (optional) = 0/1 to include/exclude volume fraction corrections in the long-range isotropic terms :ul

[Examples:]

pair_style brownian 1.5 1 1 2.01 2.5 2.0 5878567 (assuming radius = 1)
pair_coeff 1 1 2.05 2.8
pair_coeff * * :pre

[Description:]

Styles {brownian} and {brownain/poly} compute Brownian forces and
torques on finite-size particles.  The former requires monodisperse
spherical particles; the latter allows for polydisperse spherical
particles.

These pair styles are designed to be used with either the "pair_style
lubricate"_pair_lubricate.html or "pair_style
lubricateU"_pair_lubricateU.html commands to provide thermostatting
when dissipative lubrication forces are acting.  Thus the parameters
{mu}, {flaglog}, {flagfld}, {cutinner}, and {cutoff} should be
specified consistent with the settings in the lubrication pair styles.
For details, refer to either of the lubrication pair styles.

The {t_target} setting is used to specify the target temperature of
the system.  The random number {seed} is used to generate random
numbers for the thermostatting procedure.

The {flagHI} and {flagVF} settings are optional.  Neither should be
used, or both must be defined.

:line

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:

cutinner (distance units)
cutoff (distance units) :ul

The two coefficients are optional.  If neither is specified, the two
cutoffs specified in the pair_style command are used.  Otherwise both
must be specified.

:line

Styles with a {cuda}, {gpu}, {intel}, {kk}, {omp}, or {opt} suffix are
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in "this section"_Section_accelerate.html of
the manual.  The accelerated styles take the same arguments and should
produce the same results, except for round-off and precision issues.

These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
KOKKOS, USER-OMP and OPT packages, respectively.  They are only
enabled if LAMMPS was built with those packages.  See the "Making
LAMMPS"_Section_start.html#start_3 section for more info.

You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the "-suffix command-line
switch"_Section_start.html#start_7 when you invoke LAMMPS, or you can
use the "suffix"_suffix.html command in your input script.

See "this section"_Section_accelerate.html of the manual for more
instructions on how to use the accelerated styles effectively.

:line

[Mixing, shift, table, tail correction, restart, rRESPA info]:

For atom type pairs I,J and I != J, the two cutoff distances for this
pair style can be mixed.  The default mix value is {geometric}.  See
the "pair_modify" command for details.

This pair style does not support 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 does not support the "pair_modify"_pair_modify.html
tail option for adding long-range tail corrections to energy and
pressure.

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.

:line

[Restrictions:]

These styles are part of the FLD package.  They are only enabled if
LAMMPS was built with that package.  See the "Making
LAMMPS"_Section_start.html#2_3 section for more info.

Only spherical monodisperse particles are allowed for pair_style
brownian.

Only spherical particles are allowed for pair_style brownian/poly.

[Related commands:]

"pair_coeff"_pair_coeff.html, "pair_style
lubricate"_pair_lubricate.html, "pair_style
lubricateU"_pair_lubricateU.html

[Default:]

The default settings for the optional args are flagHI = 1 and flagVF =
1.