On the dielectric theory of a molecular crystalline slab with complex polarisability

Expressions for the transmission, reflection and absorption coefficients of a crystalline slab of polarisable molecules are obtained. The results are applied to one and two oscillator models with dissipation and with parameter values suggested by experimental data for the rare gas solids. The usual macroscopic, point equation of state D=ϵE, is found to give a satisfactory description of the dielectric response except near the molecular resonance frequencies. The deviations from the macroscopic theory depend on the strength of the dissipation and vary with the orientation of the slab faces with respect to the lattice and possibly the polarisation of incoming electromagnetic wave.