Refractive Index

For accurate particle size and distribution determination, especially of small particle sizes, it is necessary to know the Refractive Index (RI) of the compound.   The Refractive Index – or index of refraction – n of a substance (optical medium), is a number that describes how light, or any other radiation, propagates through that medium. The absorption part describes the amount of light being absorbed by the particle. 

The Refractive Index is determined by laser diffraction Mie theory – it is not as such a separate method. The calculation model based on Mie theory uses a refractive index to calculate the accurate particle size distribution from the light diffraction data.