Lattice heat capacity of low-dimensional systems: A pseudoelastic approximation

The lattice heat capacity of both layered and chainlike compounds has been inferred from an approximation of the vibrational spectrum, which is based upon a pseudoelastic approach. From continuum elasticity theory three modes of vibration are obtained, which are modified by the inclusion of the most dominant dispersion effects. Manageable expressions for the heat capacity are obtained, which were found to be of rather general applicability. They were used to describe the heat capacity of the chainlike diamagnetic ${\left(\mathrm{C}{\mathrm{H}}_3\right)}_4$NCd${\mathrm{Cl}}_3$, and were found to give an excellent description of the lattice contribution to the heat capacity of a variety of low-dimensional magnetic substances.