# IMPROPER

Section can be repeated.

Section used to add/remove improper in the connectivity. Useful for systems with a complex connectivity, difficult to find out automatically. [Edit on GitHub]

## Keywords

- SECTION_PARAMETERS

- ATOMS

## Keyword descriptions

SECTION_PARAMETERS: enum = ADD

  Usage: &IMPROPER (ADD|REMOVE)

  Valid values:

  - `ADD`

  - `REMOVE`

  controls the activation of the bond [Edit on GitHub]

ATOMS: integer[4]

  Keyword can be repeated.

  Usage: ATOMS {integer} {integer} {integer} {integer}

  Specifies two atomic index united by a covalent bond [Edit on GitHub]