title: 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 region of structural anomaly. It is generally thought 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 region of structural anomaly can be most reliably determined from the behavior of the excess entropy.
authors: Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk 142190, Moscow Region, Russia and Moscow Institute of Physics and Technology, 141700 Moscow, Russia.
authors: Yu D
authors: YD
authors: Fomin
authors: Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk 142190, Moscow Region, Russia and Moscow Institute of Physics and Technology, 141700 Moscow, Russia.
authors: V N
authors: VN
authors: Ryzhov
authors: High Temperature Institute, Russian Academy of Sciences, 125412, Izhorskaya 13/2, Russia.
authors: B A
authors: BA
authors: Klumov
authors: Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk 142190, Moscow Region, Russia.
authors: E N
authors: EN
authors: Tsiok