$N r, N i, alpha

Format

$N_r, N_i, alpha // float, float, float

Optical properties for shell material. N_r and N_i are real part and imaginary part of refraction index, respectively. alpha is the absorption coefficient.

The 1st line is the data for outer space, the 2nd line is the data for 1st shell, the 3rd line is the data for 2nd shell, etc.