By use of molecular dynamical simulations, liquid crystal phase transitions
and phase separations are investigated on the mixture of hard rod-like mol
ecules and hard spherical molecules. Our model for the rod-like molecule is
supposed to be a linear chain of 7 hard spheres connected with strong spri
ngs. We demonstrate that randomly added spherical molecules generally incli
ne to diminish their orientational ordering. Specially in the smectic phase
we have found that these mixing causes a phase separation, where the smect
ic rod-rich layers and sphere-rich layers are alternatively stacked in the
low concentration of spheres. In the higher concentration they show 'domain
phase: where the clusters of rod-like molecules are dispersed in the sea o
f spherical molecules, like a phase separation.