title: Curvature energy of a focal conic domain with arbitrary eccentricity
abstract: The most frequently observed focal conic domains (FCD's) in lamellar phases are those based on confocal paris of ellipse and hyperbola. Experimentally, the eccentricity of the ellipse takes a broad range of values 0</=e<1. We present an analytical expression for the curvature energy of a FCD that is valid in the entire range 0</=e<1. Generally, the curvature energy of an isolated FCD reaches a minimum only at e-->1 (under the constraint of a fixed major semiaxis of the ellipse); exceptions include situations with large saddle-splay elastic constant and small domains where the applicability of the elastic theory is limited. In realistic cases, a value of eccentricity smaller than 1 is stabilized by factors other than the curvature energy: by dislocations emerging from the FCD's with e not equal0, compression of layers and surface anchoring.
authors.affiliation: Laboratoire de Mineralogie-Cristallographie, UMR 7590, Universite de Paris-VI and Universite de Paris-VII, Case 115, 4 place Jussieu, 75252 Paris Cedex 05, France.
authors.initials: M
authors.lastname: Kleman
authors.initials: OD
authors.lastname: Lavrentovich