# pair_style command

## Syntax

    pair_style style args

- style = one of the styles from the list here
- args = arguments used by a particular style

## Examples

    pair_style gran model hertz tangential history
    pair_style none

## Description

Set the formula(s) LIGGGHTS(R)-PUBLIC uses to compute pairwise interactions. In LIGGGHTS(R)-PUBLIC, pair potentials are defined between pairs of atoms that are within a cutoff distance and the set of active interactions typically changes over time. See the bond_style command to define potentials between pairs of bonded atoms, which typically remain in place for the duration of a simulation.

The full list of pair styles defined in LIGGGHTS(R)-PUBLIC is on this page.

Hybrid models where specified pairs of atom types interact via different pair potentials can be setup using the hybrid pair style.

The coefficients associated with a pair style are typically set for each pair of atom types, and are specified by the pair_coeff command or read from a file by the read_data or read_restart commands.

The `pair_modify` command sets options for mixing of type I-J interaction coefficients.

If the pair_style command has a cutoff argument, it sets global cutoffs for all pairs of atom types. The distance(s) can be smaller or larger than the dimensions of the simulation box.

Typically, the global cutoff value can be overridden for a specific pair of atom types by the pair_coeff command. The pair style settings (including global cutoffs) can be changed by a subsequent pair_style command using the same style. This will reset the cutoffs for all atom type pairs, including those previously set explicitly by a pair_coeff command. The exceptions to this are that pair_style table and hybrid settings cannot be reset. A new pair_style command for these styles will wipe out all previously specified pair_coeff values.

The full list of pair styles defined in LIGGGHTS(R)-PUBLIC is on this page.

## Restrictions

This command must be used before any coefficients are set by the pair_coeff, read_data, or read_restart commands.

Some pair styles are part of specific packages. They are only enabled if LIGGGHTS(R)-PUBLIC was built with that package. See the Making LIGGGHTS(R)-PUBLIC section for more info on packages. The doc pages for individual pair potentials tell if it is part of a package.

## Related commands

pair_coeff, read_data, `pair_modify`, dielectric,

## Default

    pair_style none