Scattering of light by axially symmetric particles: Modification of the point-matching method

The approach based on the separation of the fields into two parts with definite properties and the proper choice of special scalar potentials for each of them is applied to the point-matching method. Earlier, such a procedure carried out within the framework of the method of separation of variables for spheroids allowed us to obtain a solution that is considerably more efficient for strongly prolate and strongly oblate particles than solutions obtained with other versions of this method. It was found that the replacement of the summation over points on the particle surface in the point-matching method by the corresponding integral leads to a faster and more exact algorithm. The applicability of the proposed method is considered in comparison with the related method of extended boundary conditions. For spheroids and Chebyshev particles with a maximum-to-minimum-size ratio exceeding 1.5–2, the efficiency of the point-matching method is not high. For other Chebyshev particles, the point-matching method is undoubtedly preferable to the commonly used method of extended boundary conditions since it allows one to increase the accuracy of calculations by several orders of magnitude. Moreover, whereas the latter method is in principle inapplicable to certain Chebyshev particles, the former lacks this disadvantage.