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	$t_{0}$	$1\times 10^{-12}$ seconds (picoseconds)
length	$l_{0}$	$1\times 10^{-10}$ metres (Angstroms)
mass	$m_{0}$	$1.66054\times 10^{-27}$ kilograms (amu)
charge	$q_{0}$	$1.60218\times 10^{-19}$ Coulombs (electron charge)
energy	$E_{0}=m_{0}(l_{0}/t_{0})^{2}$	$1.66054\times 10^{-23}$ Joules = 10 J mol$^{-1}$
pressure	$p_{0}=E_{0}/l_{0}^{3}$	$1.66054\times 10^{7}$ Pascal = 166.054 bar
Planck constant	$\hbar$	$6.35078E_{0}t_{0}$
Boltzmann constant	$k_{B}$	$0.83145E_{0}/K$

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
• Angles:
  • 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 angles:
  • 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

Versions of DL_POLY

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.

DL_POLY_4

The first DL_POLY_4 release is expected early in 2010.

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)