H-ZLAF92A by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.358949\,\lambda^2}{\lambda^2 - 0.0604086} + \frac{2.47549\,\lambda^2}{\lambda^2 - 0.0144112} + \frac{1.96702\,\lambda^2}{\lambda^2 - 131.054}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-9.7 \times 10^{-7} + 2(1.41 \times 10^{-8})\,\Delta T + 3(-3.39 \times 10^{-11})\,\Delta T^2 + \frac{1.08 \times 10^{-6} + 2(1.17 \times 10^{-9})\,\Delta T}{\lambda - 0.261}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$