title: Molecular organization of nematic liquid crystals between concentric cylinders: role of the elastic anisotropy.
abstract: The orientational order in a nematic liquid crystal sample confined to an annular region between two concentric cylinders is investigated by means of lattice Monte Carlo simulations. Strong anchoring and homeotropic orientations, parallel to the radial direction, are implemented at the confining surfaces. The elastic anisotropy is taken into account in the bulk interactions by using the pair potential introduced by Gruhn and Hess [T. Gruhn and S. Hess, Z. Naturforsch. A 51, 1 (1996)] and parametrized by Romano and Luckhurst [S. Romano, Int. J. Mod. Phys. B 12, 2305 (1998); Phys. Lett. A 302, 203 (2002); G. R. Luckhurst and S. Romano, Liq. Cryst. 26, 871 (1999)], i.e., the so-called GHRL potential. In the case of equal elastic constants, a small but appreciable deformation along the cylinder axis direction is observed, whereas when the values of K(11)/K(33) if K(22)=K(33) are low enough, all the spins in the bulk follow the orientation imposed by the surfaces. For larger values of K(11)/K(33), spontaneous deformations, perpendicular to the polar plane, increase significantly. Our findings indicate that the onset of these deformations also depends on the ratio K(22)/K(33) and on the radius of the cylindrical surfaces. Although expected from the elastic theory, no tangential component of the deformations was observed in the simulations for the set of parameters analyzed.
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Chiccoli
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Pasini
authors.affiliation: Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo, 5790-87020-900 Maringá, Paraná, Brazil.
authors.forename: L R
authors.initials: LR
authors.lastname: Evangelista
authors.affiliation: Universidade Tecnológica Federal do Paraná, Campus Apucarana, Rua Marcílio Dias 635, 86812-460 Apucarana, Paraná, Brazil.
authors.forename: R T
authors.initials: RT
authors.lastname: Teixeira-Souza
authors.affiliation: Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Zannoni