H-ZLAF76A by CDGM

$$n(\lambda) = \sqrt{1 + \frac{2.00079\,\lambda^2}{\lambda^2 - 0.01296} + \frac{1.53021\,\lambda^2}{\lambda^2 - 131.107} + \frac{0.289955\,\lambda^2}{\lambda^2 - 0.057738}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[4.09 \times 10^{-6} + 2(1.67 \times 10^{-8})\,\Delta T + 3(-4.15 \times 10^{-11})\,\Delta T^2 + \frac{1.04 \times 10^{-6} + 2(1.1 \times 10^{-9})\,\Delta T}{\lambda - 0.255}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$