It gives the scattering characteristics of both oblate and prolate spheroidal particles much smaller than the excitation wavelength.
The theory is named after Richard Gans who first published the solution for gold particles in 1912 in an article entitled "Über die Form ultramikroskopischer Goldteilchen".
[2] In Gans theory, the absorption is only dependent on the aspect ratio of the particles and not on the absolute dimensions.
This dependence is introduced through so called polarization- or shape factors related to the three dimensions of the particle.
Gans theory gives the exact solution for spheroidal particles; real nanorods, however, have a more cylindrical shape.