H-ZLAF89LA by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.32739\,\lambda^2}{\lambda^2 - 0.0540655} + \frac{2.34298\,\lambda^2}{\lambda^2 - 0.0128967} + \frac{1.76955\,\lambda^2}{\lambda^2 - 123.881}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.1 \times 10^{-6} + 2(1.42 \times 10^{-8})\,\Delta T + 3(-3.42 \times 10^{-11})\,\Delta T^2 + \frac{9.46 \times 10^{-7} + 2(9.42 \times 10^{-10})\,\Delta T}{\lambda - 0.25}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$