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.

It employs an interesting set of units with 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	$k_{B}$	$0.83145E_{0}/K$

References

1. W. Smith, C. W. Yong and P. M. Rodger "DL_POLY: application to molecular simulation", Molecular Simulation 28 pp. 385-471 (2002)