H-ZF1A by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.157527\,\lambda^2}{\lambda^2 - 0.0585467} + \frac{1.47923\,\lambda^2}{\lambda^2 - 0.0111805} + \frac{1.18166\,\lambda^2}{\lambda^2 - 115.154}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-2.07 \times 10^{-6} + 2(1.38 \times 10^{-8})\,\Delta T + 3(-4.21 \times 10^{-11})\,\Delta T^2 + \frac{7.78 \times 10^{-7} + 2(1.01 \times 10^{-9})\,\Delta T}{\lambda - 0.278}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$