H-ZBAF16 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.182248\,\lambda^2}{\lambda^2 - 0.0368485} + \frac{1.53665\,\lambda^2}{\lambda^2 - 0.00885647} + \frac{1.23072\,\lambda^2}{\lambda^2 - 134.125}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[2.86 \times 10^{-6} + 2(1.56 \times 10^{-8})\,\Delta T + 3(-3.67 \times 10^{-11})\,\Delta T^2 + \frac{7.03 \times 10^{-7} + 2(3.95 \times 10^{-10})\,\Delta T}{\lambda - 0.198}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$