Volume 79, Number 6, September 2007
Article Number 68001
Number of page(s) 5
Section Interdisciplinary Physics and Related Areas of Science and Technology
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

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

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.

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

© Europhysics Letters Association 2007