title: On the calculation of single-particle time correlation functions from Bose-Einstein centroid dynamics.
abstract: The calculation of single-particle time correlation functions using the Bose-Einstein centroid dynamics formalism is discussed. A new definition of the quasidensity operator is used to calculate the centroid force on a given particle for an anharmonic system. The force includes correlation effects due to quantum statistics and is used for the calculation of the classical-like dynamics of phase-space centroid variables within the centroid molecular dynamics approximation. Time correlation functions are then obtained for single-particle quantities. These correspond to the double-Kubo transform of exact quantum-mechanical correlation functions. The centroid dynamics results are compared to those of exact basis-set calculations and a good agreement is found. The level of accuracy is in fact the same as what was observed earlier for the calculation of center-of-mass correlation functions for Fermi-Dirac and Bose-Einstein statistics, and for any correlation function for Boltzmann statistics. These results show that it is now possible to use Bose-Einstein centroid molecular dynamics to calculate single-particle correlation functions for systems where quantum exchange effects are present.
authors.affiliation: Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2.
authors.forename: Paul
authors.initials: P
authors.lastname: Moffatt
authors.forename: Nicholas
authors.initials: N
authors.lastname: Blinov
authors.forename: Pierre-Nicholas
authors.initials: PN
authors.lastname: Roy