D-LAF79 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.265305\,\lambda^2}{\lambda^2 - 0.0420844} + \frac{1.45255\,\lambda^2}{\lambda^2 - 117.349} + \frac{1.6517\,\lambda^2}{\lambda^2 - 0.00935612}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.27 \times 10^{-6} + 2(1.38 \times 10^{-8})\,\Delta T + 3(-3.18 \times 10^{-11})\,\Delta T^2 + \frac{8.43 \times 10^{-7} + 2(4.94 \times 10^{-10})\,\Delta T}{\lambda - 0.215}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$