Onsager model for the structure of rigid rods confined on a spherical surface

Recent studies have suggested that a monolayer of self-avoiding hard rods confined on a spherical surface may display a distribution texture corresponding to splay, tennis-ball, rectangle, or cut-and-rotate splay symmetries. We investigate the system on the basis of a generalized Onsager model which includes both excluded-volume and entropic effects. The numerical solution indicates that the splay state, where on average rods line up in parallel to the longitudinal lines on the spherical surface, is the only stable state.