DL_POLY is a general purpose parallel molecular dynamics simulation package developed at Daresbury Laboratory in the United Kingdom. It was written to support academic research in the UK, but today has a world-wide user base. It was one of the first major simulation programs written specifically for parallel computers, though it is easily adapted for single processor machines, and it can be applied to a wide range of scientific areas . In Japan the program has been adopted by RIKEN and, in collaboration with Daresbury Laboratory, adapted for the Fujitsu vector-parallel machines and the unique MDGRAPE special purpose computer .