How to quantify structural anomalies in fluids?

Abstract

Some fluids are known to behave anomalously. The so-called structural anomaly which means that the fluid becomes less structures under isothermal compression is among the most frequently discussed ones. Several methods for quantifying the degree of structural order are described in the literature and are used for calculating the regions of structural anomalies. It is implied that all of the structural order determinations yield qualitatively identical results. However, no explicit comparison was made. This paper presents such a comparison for the first time. the results of some definitions are shown to contradict the intuitive notion of a fluid. On the basis of this comparison we show that the structural anomaly can be most reliably determined from the behavior of the excess entropy.

7 pages, 5 figures

References in corpus (4)

• Accurate determination of crystal structures based on averaged local bond order parameters
• Quasi-binary amorphous phase in a 3D system of particles with repulsive-shoulder interactions
• Anomalous structure and dynamics of the Gaussian-core fluid
• Anomalous phase behavior of a soft-repulsive potential with a strictly monotonic force