The refractive index is a complex number with both real and imaginary parts: (n + ki), Where "i" is the square root of -1.

The refractive index squared is equal to 1 plus the quotient of the quantity 4pi times the electron density per unit volume times the square of the charge on the electron divided by the mass of the electron times the quantity 1 divided by the quantity of the harmonic frequency of the bonding electrons squared minus the frequency of the light used to illuminate the object squared. n2 = 1 + (4(pi)Nq2/m)(l/(f02 - f2)).

Simply speaking, the refractive index increases with the number of electrons per unit volume of the material. The dispersion of the refractive index as a function of wavelength depends on the strength of the bonds between the atoms of the compound. That includes bonds between elements, molecules, and crystalline bonds. The reflectivity of a material is affected by the difference between the refractive index of the particle and that of the mounting medium.

Reflectivity (R) is equal to the quantity real part of the refractive index of the mounting medium (nm) nimus the real part of the refractive index of the reflecting object (nr) quantity squared plus the imaginary part of the refractive index (kr) squared, all divided by the real part of the refractive index of the mounting medium (nm) plus the real part of the refractive index of the reflecting object (nr) quantity squared plus the imaginary part of the refractive index (kr) squared. R = [(nm - nr)2 + kr2]/[(ni + nr)2 + kr2]

See the section on Interface Properties for documentation of these identifiable effects.