\(\renewcommand{\AA}{\text{Å}}\)

# compute erotate/sphere/atom command

## Syntax

    compute ID group-ID erotate/sphere/atom

- ID, group-ID are documented in compute command

- erotate/sphere/atom = style name of this compute command

## Examples

    compute 1 all erotate/sphere/atom

## Description

Define a computation that calculates the rotational kinetic energy for each particle in a group.

The rotational energy is computed as \(\frac12 I \omega^2\), where \(I\) is the moment of inertia for a sphere and \(\omega\) is the particle’s angular velocity.

Note

For 2d models, particles are treated as spheres, not disks, meaning their moment of inertia will be the same as in 3d.

The value of the rotational kinetic energy will be 0.0 for atoms not in the specified compute group or for point particles with a radius of 0.0.

## Output info

This compute calculates a per-atom vector, which can be accessed by any command that uses per-atom values from a compute as input. See the Howto output page for an overview of LAMMPS output options.

The per-atom vector values will be in energy units.

## Restrictions

none

## Related commands

dump custom

## Default

none