title: Inherent-structure dynamics and diffusion in liquids.
abstract: The self-diffusion constant D is expressed in terms of transitions among the local minima (inherent structures, IS) of the N-body potential-energy surface or landscape, and their correlations. The formulas are evaluated and tested against simulation in the supercooled, unit-density Lennard-Jones liquid. The approximation of uncorrelated IS-transition (IST) vectors D0, greatly exceeds D for the highest T, but merges with simulation at reduced T approximately 0.50, close to the estimated mode-coupling temperature T(c). Since uncorrelated IST's are associated with a hopping mechanism, the condition D approximately D0 provides a new way to identify the crossover to hopping. The results suggest that theories of diffusion in deeply supercooled liquids may be based on weakly correlated IST's.
authors.affiliation: Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA.
authors.forename: T
authors.initials: T
authors.lastname: Keyes
authors.forename: J
authors.initials: J
authors.lastname: Chowdhary