DL POLY

DL_POLY 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

Units

DL_POLY employs an interesting set of units which have molecular relevance .:

physical quantity	symbol	unit value
time	\(t_0 \)	\(1\times10^{-12} \) seconds (picoseconds)
length	\(l_0 \)	\(1\times10^{-10} \) metres (Angstroms)
mass	\(m_0 \)	\(1.66054\times10^{-27} \) kilograms (amu)
charge	\(q_0 \)	\(1.60218\times10^{-19} \) Coulombs (electron charge)
energy	\(E_0=m_0(l_0/t_0)^2 \)	\(1.66054\times10^{-23} \) Joules = 10 J mol\(^{-1}\)
pressure	\(p_0=E_0/l_0^3 \)	\(1.66054\times10^{7} \) Pascal = 166.054 bar
Planck constant	\(\hbar\)	\(6.35078 E_0 t_0 \)
Boltzmann constant	\(k_B\)	\(0.83145 E_0/K \)

Force field

The force field used in DL_POLY consists (or can consist) of the following components :

• Chemical bond potentials:
  • Harmonic bond potential
  • Morse potential
  • Lennard-Jones 12-6
  • Restraint bond potential
  • Quartic bond potential
  • Buckingham potential
  • FENE potential
• 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:
  • Cosine dihedral angle potential
  • Harmonic dihedral angle potential
  • Harmonic cosine dihedral angle potential
  • Triple cosine dihedral angle potential
  • Ryckaert-Bellemans dihedral angle potential
    • Flourinated Ryckaert-Bellemans dihedral angle potential
  • OPLS dihedral angle potential
• Inversion angle potentials:
  • Harmonic inversion angle potential
  • Harmonic inversion angle potential
  • Planar inversion angle potential
• Tethering potentials:
• Non-bonded potentials
• Three-body potentials
• Four-body potentials
• Metal potentials
  • Embedded atom model
  • Finnis-Sinclair
  • Sutton-Chen
  • Gupta potential
• External fields

Constraint algorithms

DL POLY can use either the SHAKE or the RATTLE algorithms as well as Q-SHAKE .

Versions of DL_POLY

The current version of DL_POLY is DL_POLY_4

Previos versions

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

DL_MULTI

A DL_POLY package to simulate rigid molecules with multipoles.

• 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)

Visualising DL_POLY output

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

External links

• DL_POLY_2.20 User Manual (PDF)
• DL_POLY_3.10 User Manual (PDF)