title: Elastic octopoles and colloidal structures in nematic liquid crystals.
abstract: We propose a simple theoretical model which explains the formation of dipolar two- (2D) and three-dimensional (3D) colloidal structures in nematic liquid crystals. The colloidal particles are treated as effective hard spheres interacting via their elastic dipole, quadrupole, and octopole moments. It is shown that the octopole moment plays an important role in the formation of 2D and 3D nematic colloidal crystals. We generalize this assumption to the case of an external electric field and theoretically explain a giant electrostriction effect in 3D crystals observed recently.
authors.affiliation: Institute of Physics, NAS Ukraine, Prospekt Nauki 46, Kyiv 03650, Ukraine.
authors.forename: S B
authors.initials: SB
authors.lastname: Chernyshuk
authors.affiliation: Bogolyubov Institute for Theoretical Physics, NAS Ukraine, Metrologichna 14-b, Kyiv 03680, Ukraine.
authors.forename: O M
authors.initials: OM
authors.lastname: Tovkach
authors.affiliation: Bogolyubov Institute for Theoretical Physics, NAS Ukraine, Metrologichna 14-b, Kyiv 03680, Ukraine.
authors.forename: B I
authors.initials: BI
authors.lastname: Lev