Engineering Documents

Title

Multiple Light Scattering from Isotropic and Anosotropic Turbid Media

Document Type

Thesis or dissertation

Date of this Version

January 1995

Comments

University of Pennsylvania, Dissertation, 1995.

Abstract

The Brownian motion of particles in a fluid is a problem with spectacular historical roots [1, 2] and continues to provide us with intriguing new physics. Recently there has been resurging interest in the first steps of these motions [3, 4, 5, 6, 7, 8]. This is largely a result of new experimental probes, such as Diffusing-Wave Spectroscopy (DWS) [7, 9, 10, 11], that enable us to measure particle displacements down to 1Å or even smaller, and thereby offer the possibility to quantitatively test hydrodynamic theories [4, 6] of nondiffusive particle motion, especially in the first random walk step. In the first experiment we present here, we use Diffusing-Wave Interferometry (DWI) [12, 13] to resolve the mean square displacement, (∆r2(τ)), of particles in hard-sphere suspensions during the first twenty nanoseconds of their motion. These are the shortest time scales ever probed in the study of Brownian dynamics.

Date Posted: 20 November 2008