Phonon density of states
= Phonon density of states
{title2=$g(\omega)=dN/d\omega$}
The number of lattice-vibration modes per unit <angular frequency>. For a three-dimensional isotropic monatomic <crystal> with three linear acoustic branches of a common speed $v_s$, wavevector-shell counting gives $g(\omega)=3V\omega^2/(2\pi^2v_s^3)$ below a suitable cutoff. Different branch speeds replace $3v_s^{-3}$ by $v_L^{-3}+2v_T^{-3}$.