Infrared extinction by homogeneous particle aggregates of SiC, FeO and SiO2: comparison of different theoretical approaches

Simple item page
dc.creatorAndersen, Anja C.
dc.creatorMutschke, Harald
dc.creatorPosch, Thomas
dc.creatorMin, Michiel
dc.creatorTamanai, Akemi
dc.date2005-11-11
dc.date.accessioned2026-07-07T06:45:02Z
dc.date.available2026-07-07T06:45:02Z
dc.descriptionParticle shape and aggregation have a strong influence on the spectral profiles of infrared phonon bands of solid dust grains. Calculating these effects is difficult due to the often extreme refractive index values in these bands. In this paper, we use the Discrete Dipole Approximation (DDA) and the T-matrix method to compute the absorption band profiles for simple clusters of touching spherical grains. We invest reasonable amounts of computation time in order to reach high dipole grid resolutions and take high multi-polar orders into account, respectively. The infrared phonon bands of three different refractory materials of astrophysical relevance are considered - Silicon Carbide (SiC), Wustite (FeO) and Silicon Dioxide (SiO2). We demonstrate that even though these materials display a range of material properties and therefore different strengths of the surface resonances, a complete convergence is obtained with none of the approaches. For the DDA, we find a strong dependence of the calculated band profiles on the exact dipole distribution within the aggregates, especially in the vicinity of the contact points between their spherical constituents. By applying a recently developed method to separate the material optical constants from the geometrical parameters in the DDA approach, we are able to demonstrate that the most critical material properties are those where the real part of the refractive index is much smaller than unity.
dc.descriptionAccepted for publication in the Journal of Quantitative Spectroscopy & Radiative Transfer (JQSRT)
dc.identifierhttps://arxiv.org/abs/astro-ph/0511371
dc.identifierhttp://arxiv.org/abs/astro-ph/0511371
dc.identifierJ.Quant.Spectrosc.Radiat.Trans. 100 (2006) 4-15
dc.identifierdoi:10.1016/j.jqsrt.2005.11.061
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/102949
dc.subjectAstrophysics
dc.titleInfrared extinction by homogeneous particle aggregates of SiC, FeO and SiO2: comparison of different theoretical approaches
dc.typetext

Files

Collections

arXiv