H-ZLAF96 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{2.5727\,\lambda^2}{\lambda^2 - 0.0148426} + \frac{0.43241\,\lambda^2}{\lambda^2 - 0.059852} + \frac{2.34871\,\lambda^2}{\lambda^2 - 156.64}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.54 \times 10^{-6} + 2(1.38 \times 10^{-8})\,\Delta T + 3(-3.21 \times 10^{-11})\,\Delta T^2 + \frac{1.17 \times 10^{-6} + 2(1.28 \times 10^{-9})\,\Delta T}{\lambda - 0.26}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$