H-ZF5 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{1.70025\,\lambda^2}{\lambda^2 - 0.0133278} + \frac{1.36323\,\lambda^2}{\lambda^2 - 122.334} + \frac{0.214513\,\lambda^2}{\lambda^2 - 0.0635763}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-4.09 \times 10^{-6} + 2(1.23 \times 10^{-8})\,\Delta T + 3(-2.03 \times 10^{-11})\,\Delta T^2 + \frac{7.19 \times 10^{-7} + 2(1.12 \times 10^{-9})\,\Delta T}{\lambda - 0.315}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$