The optical rotatory power of quartz and is variation with temperature

Abstract

Numerous formulæ have been proposed by several authors to account for the rapid increase in the rotatory power of quartz with decrease of wavelength. These formulæ generally consist of a large number of terms both positive and negative, principally of the Drude type, involving various hypothetical characteristic frequencies. An examination of these formulæ shows that they do not possess physical justification and are arbitrary in character. In the present investigation it is shown that the data are well represented by the single term formula ρ = kλ²/(λ²−λ²)² or α ν² / (ν₀²- ν²)^2' where k=7·186 and λ₀=0·0926283μ. Assuming that 'a' is a constant with temperature and ν ₀ to vary with it, the thermal variation of the optical rotatory power has been quantitatively accounted for, ν ₀ being found to vary in the same manner with temperature as estimated from the thermal variation of the refractive indices of quartz.