"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Commands_all.html)

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pair_style spin/dipole/cut command :h3
pair_style spin/dipole/long command :h3

[Syntax:]

pair_style spin/dipole/cut cutoff 
pair_style spin/dipole/long cutoff :pre

cutoff = global cutoff for magnetic dipole energy and forces
(optional) (distance units) :ulb,l
:ule

[Examples:]

pair_style spin/dipole/cut 10.0
pair_coeff * * 10.0 
pair_coeff 2 3 8.0 :pre

pair_style spin/dipole/long 9.0
pair_coeff * * 1.0 1.0
pair_coeff 2 3 1.0 1.0 2.5 4.0 scale 0.5
pair_coeff 2 3 1.0 1.0 2.5 4.0 :pre

[Description:]

Style {spin/dipole/cut} computes a short-range dipole-dipole
interaction between pairs of magnetic particles that each 
have a magnetic spin. 
The magnetic dipole-dipole interactions are computed by the
following formulas for the magnetic energy, magnetic precession 
vector omega and mechanical force between particles I and J.

:c,image(Eqs/pair_spin_dipole.jpg)

where si and sj are the spin on two magnetic particles, 
r is their separation distance, and the vector e = (Ri - Rj)/|Ri - Rj| 
is the direction vector between the two particles.  

Style {spin/dipole/long} computes long-range magnetic dipole-dipole
interaction.
A "kspace_style"_kspace_style.html must be defined to
use this pair style.  Currently, "kspace_style 
ewald/dipole/spin"_kspace_style.html and "kspace_style
pppm/dipole/spin"_kspace_style.html support long-range magnetic 
dipole-dipole interactions.

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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.

[Restrictions:]

The {spin/dipole/cut} and {spin/dipole/long} styles are part of
the SPIN package.  They are only enabled if LAMMPS was built with that 
package.  See the "Build package"_Build_package.html doc page for more 
info.

Using dipole/spin pair styles with {electron} "units"_units.html is not
currently supported.

[Related commands:]

"pair_coeff"_pair_coeff.html, "kspace_style"_kspace_style.html
"fix nve/spin"_fix_nve_spin.html

[Default:] none
