Pressure behaviour of dielectric permittivity on approaching the near-critical consolute point
Institute of Physics, Silesian University - ul. Uniwersytecka 4, 40-007 Katowice,
Accepted: 19 November 1998
Results are presented of studies on dielectric permittivity (ε) for the isothermal pressure (P) path of approaching the near-critical consolute point in 1-nitropropane–hexadecane solution. The pretransitional anomaly is well portrayed by the relation isomorphic to that applied in temperature (T) studies under atmospheric pressure. However, the anomaly is much larger, with almost negligible influence of correction-to-scaling terms and the low-frequency Maxwell-Wagner dispersion (even for ), than it was observed in temperature studies at atmospheric pressure. This makes possible a reliable estimation of a critical exponent which accounts for the critical anomaly. Discrepancies between the and the behaviour may be associated with different positions of isothermal pressure and isobaric temperature paths of approaching the critical consolute point.
PACS: 64.70.Ja – Liquid-liquid transitions / 64.60.Fr – Equilibrium properties near critical points, critical exponents / 77.22.Ch – Permittivity (dielectric function)
© EDP Sciences, 1999