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