text: For amorphous semiconductors, this statement can be determined using the Tauc-Lorentz or the Fourohi-Bloomer models.
full_question: For amorphous semiconductors, this statement can be determined using the Tauc-Lorentz or the Fourohi-Bloomer models. Examples of this kind of statement are denoted by letters such as L, R, O, and X, which appear next to figures shaped like ellipsoids, dumbbell-lemniscates, or wheel-lemniscates in a CMA diagram. In the "extraordinary" mode, this function possesses two asymptotes, which correspond to cutoff points. This function is a simple sine function for acoustic phonons, and for an electron in free-space it has a parabolic shape. Differentiating this function gives the group velocity, while dividing by the wavenumber gives the phase velocity. For 10 points, name this relation between the angular frequency and the wavenumber of a wave, which can be used to determine the frequency-dependence of a prism's index of refraction.
first_sentence: For amorphous semiconductors, this statement can be determined using the Tauc-Lorentz or the Fourohi-Bloomer models.
raw_answer: dispersion relations [or dispersion relations after "relation" is read]