Density functional theory for hard spherocylinders: phase transitions in the bulk and in the presence of external fields

The phase behaviour of hard spherocylinders is calculated using the classic al density functional theory of freezing. In particular, we construct a mod ified weighted-density approximation and calculate the bulk phase diagram. While the stability regime of the isotropic, nematic and smectic-A phases i s in reasonable agreement with computer simulation data, the theory fails t o describe the correct stability of the crystalline phases. Furthermore, we investigate the phase behaviour in an external held coupling to the orient ational degrees of freedom. As a result, bulk phases which have the same tr anslational symmetry but a different orientational symmetry can be transfor med continuously into each other above a critical strength of the external field.