Star defects on flat and spherical surfaces

(Received 11 May 1993, accepted 29 June 1993)

Abstract
We investigate the Dierker-Pindak-Meyer star defect observed in freestanding hexatic liquid crystal films. We derive general formulae for the energy of arbitrary vortex configurations both on flat films and on the surface of spherical vesicles. We find that equilibrium defect configurations in general have no identifiable symmetry and that configurations with nearly 6-fold, 5-fold, and 4-fold symmetry are possible. Configurations with nearly 5-fold symmetry are, however, favored by the conditions in the Dierker-Pindak experiment.