Hostname: page-component-848d4c4894-m9kch Total loading time: 0 Render date: 2024-05-16T09:32:54.918Z Has data issue: false hasContentIssue false

Brownian motion with stiff bonds and rigid constraints

Published online by Cambridge University Press:  26 April 2006

E. J. Hinch
Affiliation:
Department of Applied Mathematics and Theoretical Physics, The University of Cambridge, Silver Street, Cambridge CB3 9EW, UK

Abstract

Brownian systems with stiff elastic bonds of nearly constant length, such as long chain polymer molecules, behave differently when the stiff bonds are replaced by rigid bonds of exactly constant length, i.e. in statistical mechanics real stiff systems cannot be idealized by theoretical rigid ones. It is shown that a potential force can be applied to the rigidly constrained system in order to make it behave like the limit of a very stiff elastic system. A simple explicit expression for the required potential, suitable for computer simulations of the Brownian motion, is given for general constraints and also in the particular case of a trumbbell or trimer.

Type
Research Article
Copyright
© 1994 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ermak, D. L. & McCammon, J. A. 1979 Brownian dynamics with hydrodynamic interaction. J. Chem. Phys. 69, 13521360.Google Scholar
Fixman, M. 1978 Simulation of polymer dynamics. I. General theory. J. Chem. Phys. 69, 15271537.Google Scholar
Gottlieb, M. & Bird, R. B. 1976 A molecular dynamics calculation to confirm the incorrectness of the random-walk distribution for describing the Kramers freely jointed bead-rod chain. J. Chem. Phys. 65, 2467.CrossRefGoogle Scholar
Grassia, P., Hinch, E. J. & Nitsche, L. C. 1994 Computer simulations of Brownian motion of complex systems. J. Fluid Mech. (submitted)Google Scholar
Hassager, O. 1974 Kinetic theory and rheology of bead-rod models for macromolecular solutions. I. Equilibria and steady flow properties. J. Chem. Phys. 60, 21112124.Google Scholar
Helfand, E. 1979 Flexible vs rigid constraints in statistical mechanics. J. Chem Phys. 71, 50005007.Google Scholar
Hinch, E. J. & Nitsche, L. C. 1993 Nonlinear drift interactions between fluctuating colloidal particles: oscillatory and stochastic motions. J. Fluid Mech. 256, 343401.Google Scholar
Kampen van, N. G. & Lodder, J. J. 1984 Constraints. Am. J. Phys. 52, 419424.Google Scholar
Kramers, H. A. 1946 The behaviour of macromolecules in inhomogeneous flows. J. Chem. Phys. 14, 415424.Google Scholar
Rallison, J. M. 1979 The role of rigidity constraints in the rheology of dilute polymer solutions. J. Fluid Mech. 93, 251279.Google Scholar
Roy, T. K. 1990 The computer simulation of dilute solution particle dynamics. PhD thesis, Cambridge.
Uhlenbeck, G. E. & Ornstein, L. S. 1930 On the theory of the Brownian motion. Phys. Rev 36, 823841.Google Scholar