The discrete spectrum for each component problem in a Fourier decomposition of the equation of transfer is analyzed for the case of an Lth-order scattering law. The problem of determining the number of zeros of the dispersion function for each Fourier-component problem and the problem of computing all of these zeros are formulated and resolved in terms of Sturm sequences. Computational aspects of the numerical methods are discussed, and the developed algorithms are implemented to yield especially accurate numerical results for two test problems. © 1989.
Garcia, R. D. M., & Siewert, C. E. (1989). On discrete spectrum calculations in radiative transfer. Journal of Quantitative Spectroscopy and Radiative Transfer, 42(5), 385–394. https://doi.org/10.1016/0022-4073(89)90005-8