Numerical determination of the effective moments of non-spherical particles


Green, Nicolas G and Jones, Thomas B (2007) Numerical determination of the effective moments of non-spherical particles. JOURNAL OF PHYSICS D: APPLIED PHYSICS, 40, (1), 78-85.

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Description/Abstract

Dielectric characterisation of polarisable particles, and prediction of the forces and torques exerted upon them, relies on the knowledge of the effective, induced dipole moment. In turn, through the mechanism of depolarisation, the induced dipole moment of a particle is strongly dependent upon its shape. Since realistic shapes create modelling difficulties, the ‘spherical particle’ approximation is often invoked. However, in many cases, including biological dielectric spectroscopy and dielectrophoresis, this assumption is a poor one. For example, human erythrocytes are essentially oblate spheroids with indented sides, while viruses and bacteria often have elongated cigar shapes. Since shape-dependent polarisation both strongly influences the accuracy of conventional dielectric characterisation methods using Maxwell’s mixture formula and confounds accurate prediction of dielectrophoretic forces and torques, it is important to develop means to treat non-spherical particles. In this paper, we demonstrate a means to extract the dipole moment directly from numerical solutions of the induced electrostatic potential when a particle is placed in a uniform electric field. The accuracy of the method is demonstrated for a range of particle shapes: spherical, ellipsoidal, truncated cylinders and an approximation of an erythrocyte, the red blood cell.

Item Type: Article
ISSNs: 0022-3727
Keywords: dielectric theory, dielectrophoresis, numerical simulation
Divisions: Faculty of Physical Sciences and Engineering > Electronics and Computer Science > NANO
ePrint ID: 263564
Date Deposited: 19 Feb 2007
Last Modified: 27 Mar 2014 20:07
Publisher: INSTITUTE OF PHYSICS PUBLISHING
Further Information:Google Scholar
ISI Citation Count:31
URI: http://eprints.soton.ac.uk/id/eprint/263564

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