title: Localization transition of instantaneous normal modes and liquid diffusion.
abstract: We analyze the structure of instantaneous normal modes (INM) associated with the Hessian matrix of a liquid. Utilizing a scaling theory developed in the framework of Anderson localization studies, we unambiguously identify the crossover point in the INM spectrum between extended and localized modes. We establish a relation between the unstable, delocalized INMs and the liquid diffusion coefficient that appears valid over a large temperature range, covering both Arrhenius and non-Arrhenius regimes of temperature dependence. These results suggest a possible route to theoretically relate dynamics to thermodynamical properties of the liquid via the tomography of the INMs.
authors.affiliation: Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA.
authors.forename: Vasile Iulian
authors.initials: VI
authors.lastname: Clapa
authors.forename: Tsampikos
authors.initials: T
authors.lastname: Kottos
authors.forename: Francis W
authors.initials: FW
authors.lastname: Starr