Hello All, I have a question regarding complex permeability and permittivity, in particular, regarding their use with the complex refractive index in Mie theory. If the material is not dielectric, the permeability/permittivity needs to be accounted for while calculating the scattering coefficients. I have the material properties (complex refractive index and complex dielectric function) at the given wavelength. Yet, I do not have the complex permittivity or permeability. I know you can use LLG equation and derive the complex permeability, but I was wondering if there was an alternative way. Or let's say that since I do have this complex refractive index, can I simply ignore the relative permeability in the scattering coefficients? My logic says no since some materials could have a permeability of several thousand or more. I checked Kittel, Jackson, and even my trusted source in anything related to physics, Landau's books. Unless I missed something, I could not find something helpful. Can someone start me along the right path perhaps?? Thanks in advance!