H-ZBAF5 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.265136\,\lambda^2}{\lambda^2 - 0.0342929} + \frac{1.46645\,\lambda^2}{\lambda^2 - 0.00799327} + \frac{1.68212\,\lambda^2}{\lambda^2 - 179.124}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[3.26 \times 10^{-6} + 2(1.49 \times 10^{-8})\,\Delta T + 3(-2.95 \times 10^{-11})\,\Delta T^2 + \frac{6.99 \times 10^{-7} + 2(6.95 \times 10^{-10})\,\Delta T}{\lambda - 0.209}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$