# DL POLY

DL_POLY
^{[1]}
^{[2]}
is a general purpose serial and parallel molecular dynamics simulation package developed at Daresbury Laboratory by W. Smith, T.R. Forester and I.T. Todorov

## Contents

## Units[edit]

DL_POLY employs an interesting set of units which have molecular relevance ^{[3]}.:

physical quantity | symbol | unit value |

time | seconds (picoseconds) | |

length | metres (Angstroms) | |

mass | kilograms (amu) | |

charge | Coulombs (electron charge) | |

energy | Joules = 10 J mol | |

pressure | Pascal = 166.054 bar | |

Planck constant | ||

Boltzmann constant |

## Force field[edit]

The force field used in DL_POLY consists (or can consist) of the following components ^{[4]}:

- Chemical bond potentials:
- Angle potentials:
- Harmonic angle potential
- Quartic angle potential
- Truncated harmonic angle potential
- Screened harmonic angle potential
- Screened Vessal angle potential
- Truncated Vessal angle potential
- Harmonic cosine angle potential
- Cosine angle potential
- MM stretch-bend angle potential
- COMPASS stretch-stretch
- COMPASS stretch-bend
- COMPASS all terms

- Dihedral angle potentials:
- Inversion angle potentials:
- Tethering potentials:
- Non-bonded potentials
- Three-body potentials
- Four-body potentials
- Metal potentials
- External fields

## Constraint algorithms[edit]

DL POLY can use either the SHAKE or the RATTLE algorithms as well as Q-SHAKE ^{[5]}.

## Versions of DL_POLY[edit]

The current version of DL_POLY is DL_POLY_4.07

#### Previous versions[edit]

- DL_POLY_2

DL_POLY_2 was designed for simulations of up to 30,000 atoms and on parallel computers using up to 100 processors.

- DL_POLY_3

DL_POLY_3 was designed for simulations of order 100,000 to 1,000,000 atoms running on up to 1000 processors.

- DL_POLY_3 does not handle rigid body molecules.

#### Other versions[edit]

- DL_MULTI

A DL_POLY package to simulate rigid molecules with multipoles ^{[6]}.

## Visualising DL_POLY output[edit]

The visualisation program VMD is capable of displaying the HISTORY trajectory file.

## References[edit]

- ↑ W. Smith and T. R. Forester "DL_POLY_2.0: A general-purpose parallel molecular dynamics simulation package", Journal of Molecular Graphics
**14**pp. 136-141 (1996) - ↑ W. Smith, C. W. Yong and P. M. Rodger "DL_POLY: application to molecular simulation", Molecular Simulation
**28**pp. 385-471 (2002) - ↑ source: DL_POLY User Manual (v. 2.20) § 1.3.10
- ↑ source: DL_POLY User Manual (v. 2.20) § 4.1.3
- ↑ source: DL_POLY User Manual (v. 2.20) § 2.5.2
- ↑ M. Leslie "DL_MULTI—A molecular dynamics program to use distributed multipole electrostatic models to simulate the dynamics of organic crystals", Molecular Physics
**106**pp. 1567-1578 (2008)