Date recorded: March 17 2020

Geologists may know more about optical properties and their empirical determination than many so-called light scattering ‘experts’. A large number of materials can either be considered mixtures or part of a family of homologues from the optical properties point-of-view. With some very broad assumptions surprisingly excellent values for optical properties can be predicted by the Gladstone-Dale approach. We will discuss this approach together with molar refractivity routes to refractive index prediction for organic molecules.