Phase diagram and water-like anomalies in core-softened shoulder-dumbbells system

Using molecular dynamics we studied the role of the anisotropy on the phase boundary and on the anomalous behavior of 250 dimeric particles interacting by a core-softened potential. This study led us to an unexpected result: the introduction of a rather small anisotropy, quantified by the distance between the particles inside each dimer, leads to the increase of the size of the regions in the pressure-temperature phase diagram of anomalies when compared to the isotropic monomeric case. However, as the anisotropy increases beyond a threshold the anomalous regions shrinks. We found that this behavior can be understood by decoupling the translational and non-translational kinetic energy components into different translational and non-translational temperatures.