# pair_style lcbop command

## Syntax

``` LAMMPS
pair_style lcbop
```

## Examples

``` LAMMPS
pair_style lcbop
pair_coeff * * ../potentials/C.lcbop C
```

## Description

The *lcbop* pair style computes the long-range bond-order potential for
carbon (LCBOP) of [(Los and Fasolino)](Los). See section II in that
paper for the analytic equations associated with the potential.

Only a single pair_coeff command is used with the *lcbop* style which
specifies an LCBOP potential file with parameters for specific elements.
These are mapped to LAMMPS atom types by specifying N additional
arguments after the filename in the pair_coeff command, where N is the
number of LAMMPS atom types:

-   filename
-   N element names = mapping of LCBOP elements to atom types

See the [pair_coeff](pair_coeff) page for alternate ways to specify the
path for the potential file.

As an example, if your LAMMPS simulation has 4 atom types and you want
the first 3 to be C you would use the following pair_coeff command:

``` LAMMPS
pair_coeff * * C.lcbop C C C NULL
```

The first 2 arguments must be \* \* so as to span all LAMMPS atom types.
The first C argument maps LAMMPS atom type 1 to the C element in the
LCBOP file. If a mapping value is specified as NULL, the mapping is not
performed. This can be used when a *lcbop* potential is used as part of
the *hybrid* pair style. The NULL values are placeholders for atom types
that will be used with other potentials.

The parameters/coefficients for the LCBOP potential as applied to C are
listed in the C.lcbop file to agree with the original [(Los and
Fasolino)](Los) paper. Thus the parameters are specific to this
potential and the way it was fit, so modifying the file should be done
carefully.

------------------------------------------------------------------------

## Mixing, shift, table, tail correction, restart, rRESPA info

This pair style does not support the [pair_modify](pair_modify) mix,
shift, table, and tail options.

This pair style does not write its information to [binary restart
files](restart), since it is stored in potential files. Thus, you need
to re-specify the pair_style and pair_coeff commands 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) command. It does not support the *inner*,
*middle*, *outer* keywords.

## Restrictions

This pair style is part of the MANYBODY package. It is only enabled if
LAMMPS was built with that package. See the [Build
package](Build_package) page for more info.

This pair potential requires the [newton](newton) setting to be \"on\"
for pair interactions.

The `C.lcbop` potential file provided with LAMMPS (see the potentials
directory) is parameterized for [metal units](units). You can use the
LCBOP potential with any LAMMPS units, but you would need to create your
own LCBOP potential file with coefficients listed in the appropriate
units if your simulation does not use \"metal\" units.

## Related commands

[pair_airebo](pair_airebo), [pair_coeff](pair_coeff)

## Default

none

------------------------------------------------------------------------

::: {#Los}
**(Los and Fasolino)** J. H. Los and A. Fasolino, Phys. Rev. B 68,
024107 (2003).
:::