Evidence for Smectic Order in a Fluid of Hard Parallel Spherocylinders

We present Monte Carlo simulations on systems of parallel spherocylinders with length-to-width ratios $\frac{L}{D}$ between 0.25 and 5. We have determined the solid-liquid coexistence points in these systems by computing the absolute free energy of the solid and fluid phases. In addition we find that for $\frac{L}{D}>0.5\mathrm{}$ a thermodynamically stable smectic phase is formed at densities well below the thermodynamic melting point. The transition from nematic to smectic appears to be continuous. We find no evidence for long-range bond-orientational order in the smectic phase.