Evaluate the simplified integral and introduce the
Debye frequency $\omega_{\text{D}}=k_{\text{D}}c$
and the Debye temperature $\Theta_{\text{D}}$ which is given by
Evaluate the simplified integral and introduce the
Debye frequency $\omega_{\text{D}}=k_{\text{D}}c$
and the Debye temperature $\Theta_{\text{D}}$ which is given by