Magnetic-Field-Induced Weak Order in Nematic Liquid Crystals Formed by Biaxial Molecules

Nematic liquid crystal system of interacting biaxial particles via dispersion forces is studied. The molecular orienting potential form in a magnetic field is given for the first time. Weakly ordered isotropic phase is treated in the two-particle cluster approximation. Taking account of the molecular biaxiality, it is found that the ratio of the lowest supercooling temperature T* to the nematic-isotropic phase transition temperature Tc approaches the observed value, and the validity of the mean field theory is clarified.