Correct microcanonical ensemble in molecular dynamics.
The statistical-mechanics ensemble corresponding to equilibrium molecular dynamics simulations is different than the usual microcanonical EVN ensemble. Historically molecular dynamics has been associated with the EVNM ensemble, where M is the constant total linear momentum of the system. We show that the correct ensemble associated with molecular dynamics is the EVNMG ensemble where G is the constant of the motion associated with Galilean boosts. The ensemble associated with molecular dynamics simulations has, apparently, not been previously recognized. An earlier problem with the pressure in the new ensemble disappears.
Ray
J R
JR
Department of Physics and Astronomy, Kinard Laboratory of Physics, Clemson University, Clemson, South Carolina 29634-1911, USA.
Zhang
H
H