Tetrahedratic mesophases, chiral order, and helical domains induced by quadrupolar and octupolar interactions

摘要: We present an exhaustive account of phases and phase transitions that can be stabilized in the recently introduced generalized Lebwohl-Lasher model with quadrupolar octupolar microscopic interactions [L. Longa, G. Paj ˛ ak, T. Wydro, Phys. Rev. E 79, 040701(R) (2009)]. A complete mean-field analysis model, along Monte Carlo simulations allows us to identify four distinct classes diagrams a number multicritical points where, addition standard uniaxial biaxial nematic phases, other like are stabilized. These involve, among others, tetrahedratic (T ), (NT chiral (N ∗ T ) global Td , D2d ,a ndD2 symmetry, respectively. Molecular order parameters correlation functions these determined. conclude generalizations give simple molecular interpretation macroscopic regions opposite optical activity (ambidextrous chirality), observed, e.g., bent-core systems. An estimate helical pitch N is also given.