Issue
EPL
Volume 79, Number 6, September 2007
Article Number 68001
Number of page(s) 5
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/79/68001
Published online 21 August 2007
EPL, 79 (2007) 68001
DOI: 10.1209/0295-5075/79/68001

High-order correlation contributions to the friction of macromolecules in solution: A semi-phenomenological Fokker-Planck approach

A. Uvarov and S. Fritzsche

Institut für Physik, Universität Kassel - Heinrich-Plett-Str. 40, D-34132 Kassel, Germany

uvarov@physik.uni-kassel.de

received 19 February 2007; accepted in final form 29 July 2007; published September 2007
published online 21 August 2007

Abstract
A novel, semi-phenomenological expression is derived for the friction tensor of macromolecules immersed into solution. By making a few realistic assumptions about the interaction of the molecular beads with the particles of the solvent, the friction tensor is expanded into a series of terms which purely depend on the (j+2)-point correlation functions of the solvent as defined in the kinetic theory of the liquids. In a first application of this series expansion, the boundary condition coefficient is investigated for a single bead in dependence on the strength of the interaction among the solvent particles and with the macromolecule. When compared with previous molecular-dynamical simulations, excellent agreement is found even for a rather strong coupling between the bead and the solvent. Our new semi-phenomenological approach may therefore help extend the study of transport properties towards complex macromolecules in solution and will reduce the computational costs for that by several order of magnitude.

PACS
82.60.Lf - Thermodynamics of solutions.
82.35.Lr - Physical properties of polymers.
67.40.Fd - Dynamics of relaxation phenomena.

© Europhysics Letters Association 2007