Abstract
BC (Black Carbon), which can be found in the atmosphere, is characterized
by a large value of the imaginary part of the complex refractive index
and, therefore, might have an impact on the global warming effect. To
study the interaction of BC with light often computer simulations are
used. One of the methods, which are capable of performing light scattering
simulations by any shape, is DDA (Discrete Dipole Approximation). In this
work its accuracy was estimated in respect to BC structures using the
latest stable version of the ADDA (vr. 1.2) algorithm. As the reference
algorithm the GMM (Generalized Multiparticle Mie-Solution) code was used.
The study shows that the number of volume elements (dipoles) is the main
parameter that defines the quality of results. However, they can be
improved by a proper polarizability expression. The most accurate, and
least time consuming, simulations were observed for IGT_SO. When an
aggregate consists of particles composed of ca. 750 volume elements
(dipoles), the averaged relative extinction error should not exceed ca.
4.5%.
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