## Abstract

The purpose of this work is to show that an appropriate multiple *T*-matrix formalism can be useful in performing qualitative studies of the optical properties of colloidal systems composed of nonspherical objects (despite limitations concerning nonspherical particle packing densities). In this work we have calculated the configuration averages of scattering and absorption cross sections of different clusters of dielectric particles. These clusters are characterized by their refraction index, particle shape, and filling fraction. Computations were performed with the recursive centered *T*-matrix algorithm (RCTMA), a previously established method for solving the multiple scattering equation of light from finite clusters of isotropic dielectric objects. Comparison of the average optical cross sections between the different systems highlights variations in the scattering and absorption properties due to the electromagnetic interactions, and we demonstrate that the magnitudes of these quantities are clearly modulated by the shape of the primary particles.

© 2007 Optical Society of America

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### Equations (5)

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(1)
$${\mathbf{E}}_{\mathit{inc}}={E}_{0}\sum _{n=1}^{\infty}\sum _{m=-n}^{n}[Rg\left\{{\Psi}_{1nm}^{t}\left(k\mathbf{r}\right)\right\}{a}_{1nm}+Rg\left\{{\Psi}_{2nm}^{t}\left(k\mathbf{r}\right)\right\}{a}_{2nm}]\equiv {E}_{0}Rg\left\{{\Psi}^{t}\left(k\mathbf{r}\right)\right\}a,$$
(2)
$${\mathbf{E}}_{\mathit{sca}}^{\left(i\right)}={E}_{0}\sum _{n=1}^{\infty}\sum _{m=-n}^{n}[{\Psi}_{1nm}^{t}\left(k{\mathbf{r}}_{i}\right){f}_{1nm}^{\left(i\right)}+{\Psi}_{2nm}^{t}\left(k{\mathbf{r}}_{i}\right){f}_{2nm}^{\left(i\right)}]\equiv {E}_{0}{\Psi}^{t}\left(k{\mathbf{r}}_{i}\right){f}^{\left(i\right)},$$
(3)
$${\mathbf{E}}_{\mathit{exc}}^{\left(i\right)}=Rg\{{\Psi}^{t}\left(k{\mathbf{r}}_{i}\right)\}[{J}^{(i,0)}a+\sum _{\begin{array}{c}j=1\\ j\ne i\end{array}}^{j=N}{H}^{(i,j)}{f}^{\left(j\right)}]\equiv Rg\left\{{\Psi}^{t}\left(k{\mathbf{r}}_{i}\right)\right\}{e}^{\left(i\right)},$$
(4)
$${f}^{\left(i\right)}={T}_{1}^{\left(i\right)}[{J}^{(i,0)}a+\sum _{\begin{array}{c}j=1\\ j\ne i\end{array}}^{j=N}{H}^{(i,j)}{f}^{\left(j\right)}],\phantom{\rule{1em}{0ex}}\phantom{\rule{1em}{0ex}}i=1,\dots ,N.$$
(5)
$${T}_{N}^{\left(i\right)}={T}_{1}^{\left(i\right)}[\stackrel{\mathrm{\u20e1}}{\mathbf{I}}+\sum _{\begin{array}{c}j=1\\ j\ne i\end{array}}^{N}{H}^{(i,j)}{T}_{N}^{\left(j\right)}{J}^{(j,i)}],\phantom{\rule{1em}{0ex}}\phantom{\rule{1em}{0ex}}i=1,\dots ,N.$$