We have mapped out the complete phase diagram of hard spherocylinders as a function of the shape anisotropy . Special computational techniques were required to locate phase transitions in the limit and in the close-packing limit for . The phase boundaries of five different phases were established: the isotropic fluid, the liquid crystalline smectic A and nematic phases, the orientationally ordered solids—in AAA and ABC stacking—and the plastic or rotator solid. The rotator phase is unstable for and the AAA crystal becomes unstable for lengths smaller than . The triple points isotropic-smectic-A-solid and isotropic-nematic-smectic-A are estimated to occur at and , respectively. For the low region, a modified version of the Gibbs–Duhem integration method was used to calculate the isotropic-solid coexistence curves. This method was also applied to the I-N transition for . For large the simulation results approach the predictions of the Onsager theory. In the limit simulations were performed by application of a scaling technique. The nematic-smectic-A transition for appears to be continuous. As the nematic-smectic-A transition is certainly of first order nature for , the tri-critical point is presumably located between and . In the small region, the plastic solid to aligned solid transition is first order. Using a mapping of the dense spherocylinder system on a lattice model, the initial slope of the coexistence curve could even be computed in the close-packing limit.
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Research Article| January 08 1997
Tracing the phase boundaries of hard spherocylinders
Peter Bolhuis, Daan Frenkel; Tracing the phase boundaries of hard spherocylinders. J. Chem. Phys. 8 January 1997; 106 (2): 666–687. https://doi.org/10.1063/1.473404
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