Quantum Molecular Dynamics O(N) TightBinding on the.pdf

Quantum Molecular Dynamics ON TightBinding on the TD  A Canning G Gal li F Mauri A De Vita and R Car IRRMA Institut Romand de Recherche Numerique en Physique des Materiaux EPFL Lausanne Switzerland Cray Research Switzerland PSE EPFL Abstract even with the most p owerful mo dern computers Tight Binding TB mo dels while still presenting a quantum We discuss the implementation of an ON tightbinding mechanical approach to molecular dynamics have a much molecular dynamics co de on the Cray TD parallel com simpler Hamiltonian and smaller basis set greatly reducing puter The lo calisation intro duces a sparse nature to the the computational cost of an MD step However the scal orbital data and Hamiltonian matrix greatly changing the 3 ing of the computational cost is still of O N even though co ding on parallel machines compared to nonlo calised sys the prefactor is much smaller than for rstprinciples cal tems The data distribution communication routines and culations This limits the numb er of atoms that can b e dynamic loadbalancing schem