A low-density mixture of rod-like and plate-like molecules forms an isotropic phase. Both rod and plate axes are randomly oriented. At higher density, a uniaxial nematic phase may appear. Depending on composition, this may be dominated by the rods (illustrated here) or the plates. At still higher density the system may form a biaxial phase, with two preferred directions, or it may separate into two phases, one rod-rich, the other plate-rich. We see both in our simulations. The two-phase system is simulated by a special technique known as Gibbs ensemble Monte Carlo.
P J Camp, M P Allen, P G Bolhuis, D Frenkel
J Chem Phys, 106, 9270-9275 (1997).
60:40 mixture of rods and plates; nematic phase. The orientation spheroid for each species appears in the corner.