Intrinsic viscosity from the Green–Kubo formula

Abstract

The Green–Kubo formalism and the conventional Kirkwood–Riseman formalism (with and without hydrodynamic preaveraging approximation) are compared in the calculation of the intrinsic viscosity of a Gaussian chain. It is discussed that the Green–Kubo-type formula for the intrinsic viscosity is correct to order ε(=4−d, d being the spatial dimension). Then it is shown that without self-avoiding interaction the two formalisms give identical results to order ε; i.e., the Kirkwood–Riseman formalism is as reliable as the Green–Kubo formalism without self-avoiding interactions. With self-avoiding interaction it is argued that the validity of the Kirkwood–Riseman formalism cannot be expected.