H-ZLAF78B by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.299637\,\lambda^2}{\lambda^2 - 0.0470546} + \frac{2.19453\,\lambda^2}{\lambda^2 - 0.0115404} + \frac{1.53572\,\lambda^2}{\lambda^2 - 112.609}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-4.39 \times 10^{-7} + 2(1.46 \times 10^{-8})\,\Delta T + 3(-2.76 \times 10^{-11})\,\Delta T^2 + \frac{8.87 \times 10^{-7} + 2(7.53 \times 10^{-10})\,\Delta T}{\lambda - 0.22}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$