Abstract
Recent Monte Carlo studies have demonstrated the existence of positionally ordered phases in systems of monodisperse, parallel hard spherocylinders. We present an excluded-volume theory of this system which utilizes a scaled-particle treatment of dimensions possessing full translational freedom combined with a simple cell model for positionally ordered dimensions. The calculated phase diagram is in excellent qualitative agreement with the Monte Carlo results, exhibiting regions of nematic, smectic, columnar, and crystalline stability.