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,v, find the Debye temperature (a) for a unidimensional crystal, i.e. a chain of identical atoms, incorporating n0n_{0} atoms per unit length; (b) for a two-dimensional crystal, i.e. a plane square grid consisting of identical atoms, containing n0n_{0} atoms per unit area; (c) for a simple cubic lattice consisting of identical atoms, containing n0n_{0} atoms per unit volume.

Reveal Answer
(a) Θ=(/k)πvn0\Theta=(\hbar / k) \pi v n_{0} (b) Θ=(/k)v4πn0\Theta=(\hbar / k) v \sqrt{4 \pi n_{0}} (c) Θ=\Theta= =(/k)v6π2n03=(\hbar / k) v \sqrt[3]{6 \pi^{2} n_{0}}