# angle_coeff command

## Syntax

``` LAMMPS
angle_coeff N args
```

-   N = numeric angle type (see asterisk form below), or type label
-   args = coefficients for one or more angle types

## Examples

``` LAMMPS
angle_coeff 1 300.0 107.0
angle_coeff * 5.0
angle_coeff 2*10 5.0

labelmap angle 1 hydroxyl
angle_coeff hydroxyl 300.0 107.0
```

## Description

Specify the angle force field coefficients for one or more angle types.
The number and meaning of the coefficients depends on the angle style.
Angle coefficients can also be set in the data file read by the
[read_data](read_data) command or in a restart file.

$N$ can be specified in one of two ways. An explicit numeric value can
be used, as in the first example above. Or $N$ can be a type label,
which is an alphanumeric string defined by the [labelmap](labelmap)
command or in a section of a data file read by the
[read_data](read_data) command.

For numeric values only, a wild-card asterisk can be used to set the
coefficients for multiple angle types. This takes the form \"\*\" or
\"\*n\" or \"n\*\" or \"m\*n\". If $N$ is the number of angle types,
then an asterisk with no numeric values means all types from 1 to $N$. A
leading asterisk means all types from 1 to n (inclusive). A trailing
asterisk means all types from n to $N$ (inclusive). A middle asterisk
means all types from m to n (inclusive).

Note that using an [angle_coeff](angle_coeff) command can override a
previous setting for the same angle type. For example, these commands
set the coeffs for all angle types, then overwrite the coeffs for just
angle type 2:

``` LAMMPS
angle_coeff * 200.0 107.0 1.2
angle_coeff 2 50.0 107.0
```

A line in a data file that specifies angle coefficients uses the exact
same format as the arguments of the [angle_coeff](angle_coeff) command
in an input script, except that wild-card asterisks should not be used
since coefficients for all $N$ types must be listed in the file. For
example, under the \"Angle Coeffs\" section of a data file, the line
that corresponds to the first example above would be listed as

    1 300.0 107.0

The [angle_style class2](angle_class2) is an exception to this rule, in
that an additional argument is used in the input script to allow
specification of the cross-term coefficients. See its doc page for
details.

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

The list of all angle styles defined in LAMMPS is given on the
[angle_style](angle_style) doc page. They are also listed in more
compact form on the [Commands angle](angle) doc page.

On either of those pages, click on the style to display the formula it
computes and its coefficients as specified by the associated
[angle_coeff](angle_coeff) command.

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

## Restrictions

This command must come after the simulation box is defined by a
[read_data](read_data), [read_restart](read_restart), or
[create_box](create_box) command.

An angle style must be defined before any angle coefficients are set,
either in the input script or in a data file.

## Related commands

[angle_style](angle_style)

## Default

none