H-ZF11 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{1.59868\,\lambda^2}{\lambda^2 - 0.0126058} + \frac{0.189449\,\lambda^2}{\lambda^2 - 0.0617895} + \frac{1.2687\,\lambda^2}{\lambda^2 - 121.377}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-5.39 \times 10^{-6} + 2(1.28 \times 10^{-8})\,\Delta T + 3(-5.25 \times 10^{-11})\,\Delta T^2 + \frac{9.07 \times 10^{-7} + 2(9.29 \times 10^{-10})\,\Delta T}{\lambda - 0.278}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$