D-ZF93 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{1.51324\,\lambda^2}{\lambda^2 - 106.263} + \frac{2.1674\,\lambda^2}{\lambda^2 - 0.0142319} + \frac{0.606108\,\lambda^2}{\lambda^2 - 0.0666587}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.28 \times 10^{-5} + 2(3.34 \times 10^{-8})\,\Delta T + 3(-1.53 \times 10^{-10})\,\Delta T^2 + \frac{2.75 \times 10^{-6} + 2(2.52 \times 10^{-9})\,\Delta T}{\lambda - 0.299}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$