\(\renewcommand{\AA}{\text{Å}}\)

# angle_style gaussian command

## Syntax

    angle_style gaussian

## Examples

    angle_style gaussian
    angle_coeff 1 300.0 2 0.0128 0.375 80.0 0.0730 0.148 123.0

## Description

The gaussian angle style uses the potential:

\[E = -k_B T ln\left(\sum_{i=1}^{n} \frac{A_i}{w_i \sqrt{\pi/2}} exp\left( \frac{-2(\theta-\theta_{i})^2}{w_i^2}\right) \right)\]

This analytical form is a suitable potential for obtaining mesoscale effective force fields which can reproduce target atomistic distributions (Milano).

The following coefficients must be defined for each angle type via the angle_coeff command as in the example above, or in the data file or restart files read by the read_data or read_restart commands:

- \(T\) temperature at which the potential was derived

- \(n\) (integer >=1)

- \(A_1\) (> 0, radians)

- \(w_1\) (> 0, radians)

- \(\theta_1\) (degrees)

- …

- \(A_n\) (> 0, radians)

- \(w_n\) (> 0, radians)

- \(\theta_n\) (degrees)

## Restrictions

This angle style can only be used if LAMMPS was built with the EXTRA-MOLECULE package. See the Build package doc page for more info.

## Related commands

angle_coeff

## Default

none

(Milano) G. Milano, S. Goudeau, F. Mueller-Plathe, J. Polym. Sci. B Polym. Phys. 43, 871 (2005).