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**Harvard**

Kahnert, M. (2013) *T-matrix computations for particles with high-order finite symmetries*.

** BibTeX **

@article{

Kahnert2013,

author={Kahnert, Michael},

title={T-matrix computations for particles with high-order finite symmetries},

journal={Journal of Quantitative Spectroscopy and Radiative Transfer},

issn={0022-4073},

volume={123},

pages={79-91},

abstract={The use of group theoretical methods can substantially reduce numerical ill-conditioning problems in T-matrix computations. There are specific problems related to obtaining the irreducible characters of high-order symmetry groups and to the construction of a transformation from the basis of vector spherical wave functions to the irreducible basis of high-order symmetry groups. These problems are addressed, and numerical solutions are discussed and tested. An important application of the method is non-convex particles perturbed with high-order polynomials. Such morphologies can serve as models for particles with small-scale surface roughness, such as mineral aerosols, atmospheric ice particles with rimed surfaces, and various types of cosmic dust particles. The method is tested for high-order 3D-Chebyshev particles, and the performance of the method is gauged by comparing the results to computations based on iteratively solving a Lippmann-Schwinger T-matrix equation. The latter method trades ill-conditioning problems for potential slow-convergence problems, and it is rather specific, as it is tailored to particles with small-scale surface roughness. The group theoretical method is general and not plagued by slow-convergence problems. The comparison of results shows that both methods achieve a comparable numerical stability. This suggests that for particles with high-order symmetries the group-theoretical approach is able to overcome the illconditioning problems. Remaining numerical limitations are likely to be associated with loss-of-precision problems in the numerical evaluation of the surface integrals.},

year={2013},

keywords={Scattering, T-matrix, Mineral dust, Cosmic dust, Ice clouds, electromagnetic scattering, formulation },

}

** RefWorks **

RT Journal Article

SR Electronic

ID 179407

A1 Kahnert, Michael

T1 T-matrix computations for particles with high-order finite symmetries

YR 2013

JF Journal of Quantitative Spectroscopy and Radiative Transfer

SN 0022-4073

VO 123

SP 79

OP 91

AB The use of group theoretical methods can substantially reduce numerical ill-conditioning problems in T-matrix computations. There are specific problems related to obtaining the irreducible characters of high-order symmetry groups and to the construction of a transformation from the basis of vector spherical wave functions to the irreducible basis of high-order symmetry groups. These problems are addressed, and numerical solutions are discussed and tested. An important application of the method is non-convex particles perturbed with high-order polynomials. Such morphologies can serve as models for particles with small-scale surface roughness, such as mineral aerosols, atmospheric ice particles with rimed surfaces, and various types of cosmic dust particles. The method is tested for high-order 3D-Chebyshev particles, and the performance of the method is gauged by comparing the results to computations based on iteratively solving a Lippmann-Schwinger T-matrix equation. The latter method trades ill-conditioning problems for potential slow-convergence problems, and it is rather specific, as it is tailored to particles with small-scale surface roughness. The group theoretical method is general and not plagued by slow-convergence problems. The comparison of results shows that both methods achieve a comparable numerical stability. This suggests that for particles with high-order symmetries the group-theoretical approach is able to overcome the illconditioning problems. Remaining numerical limitations are likely to be associated with loss-of-precision problems in the numerical evaluation of the surface integrals.

LA eng

DO 10.1016/j.jqsrt.2012.08.004

LK http://dx.doi.org/10.1016/j.jqsrt.2012.08.004

LK http://publications.lib.chalmers.se/records/fulltext/179407/local_179407.pdf

OL 30