H-ZBAF3 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.175552\,\lambda^2}{\lambda^2 - 0.0360805} + \frac{1.51567\,\lambda^2}{\lambda^2 - 0.00823044} + \frac{1.11141\,\lambda^2}{\lambda^2 - 113.992}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.39 \times 10^{-6} + 2(1.54 \times 10^{-8})\,\Delta T + 3(-4.1 \times 10^{-11})\,\Delta T^2 + \frac{5.46 \times 10^{-7} + 2(5.06 \times 10^{-10})\,\Delta T}{\lambda - 0.206}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$