Rotational Phase Transition and Melting in a Two-Dimensional Hard-Cyclic-Tetramer System

Abstract
Mechanical simulations of a two-dimensional system of N cyclic tetramers, studied in square (N=289) and hexagonal (N=331) boxes, demonstrate the existence of crystalline d=VV01.14; different structures are observed), rotator (1.18d1.29), and fluid (d1.31) phases (V0 is the area of the box with close-packed structure). Observed phase coexistences suggest first-order transitions.