All Problems

Molecules and Crystals

Problem 6.185

Assuming the propagation velocities of longitudinal and transverse vibrations to be the same and equal to \(v,\) find the Debye temperature (a) for a unidimensional crystal, i.e. a chain of identical atoms, incorporating \(n_{0}\) atoms per unit length; (b) for a two-dimensional crystal, i.e. a plane square grid consisting of identical atoms, containing \(n_{0}\) atoms per unit area; (c) for a simple cubic lattice consisting of identical atoms, containing \(n_{0}\) atoms per unit volume.

Reveal Answer
(a) \(\Theta=(\hbar / k) \pi v n_{0}\) (b) \(\Theta=(\hbar / k) v \sqrt{4 \pi n_{0}}\) (c) \(\Theta=\) \(=(\hbar / k) v \sqrt[3]{6 \pi^{2} n_{0}}\)