A molecular calculation of electronic properties of layered crystals. II. Periodic small cluster calculation for graphite and boron nitride

For pt.I, see ibid., vol.7, 76 (1974). Small (18-32 atoms) periodic clusters of two-dimensional hexagonal graphite and boron nitride are shown to represent some high-symmetry points in the Brillouin zone of the infinite crystal. Semi-empirical all-valence electron calculations are performed on these clusters and the binding energy, work function, bandwidth, band-to-band transition energy, band gap, charges and equilibrium distances are computed and compared with values obtained by tight binding and truncated crystal calculations. Favourable agreement with experimental data is obtained with selfconsistent calculations on these clusters.