Molecular dynamics calculation for the modified xy model

Abstract

In order to demonstrate the effectiveness of molecular dynamics (MD) for the determination of the density of states of a system that suffers an abrupt change of state, the authors performed extensive calculations for the modified rotor model, defined by a specific interaction potential between neighboring rotors. Their results for 2-dimensional L [times] L lattices with L = 8, 16, 32, and 64 demonstrate clearly that the transition is continuous for p[sup 2] [le] 24, but suggest a first-order transition for p[sup 2] [ge] 28.