Low Temperature Physics: 33, 790 (2007); https://doi.org/10.1063/1.2781507 (7 pages)
Физика Низких Температур: Том 33, Выпуск 9 (Сентябрь 2007), c. 1036-1044    ( к оглавлению , назад )

Collective excitations in dynamics of liquids: a "toy" dynamical model for binary mixtures

T. Bryk1,2 and I.M. Mryglod1,2

1Institute for Condensed Matter Physics of National Academy of Sciences of Ukraine 1 Svientsitskii Str., Lviv 79011, Ukraine
E-mail: mryglod@icmp.lviv.ua

2 Institute of Applied Mathematics and Fundamental Sciences of National Technical University of Lviv Lviv 79013, Ukraine

Received January 18, 2007


We propose a new «toy» dynamical model that permits us to derive analytical expressions for dispersion of two branches of «bare» propagating collective excitations in binary disordered systems in the whole range of wavenumbers. These expressions are used for the analysis of dependence of dispersion curves on mass ratio and concentration at fixed density of the system. An effect of hybridization of two branches is discussed in terms of mode contributions to time correlation functions. This allows us to estimate the regions with dominant types of coherent or partial dynamics.

PACS: 05.20.Jj Statistical mechanics of classical fluids;
PACS: 61.20.Lc Time-dependent properties; relaxation;
PACS: 61.25.Mv Liquid metals and alloys.

Key words: collective excitations, dispersion law, binary liquids, molecular dynamics.