Low-frequency dielectric dispersion and electric conductivity near the consolute point in some binary liquid mixtures

Pressure behaviour of dielectric permittivity on approaching the near-critical consolute point

“…The figure also contains the pressure scale transformed to the temperature one, which makes the comparison with isobaric temperature studies easier. The visible systematic shift of the dielectric permittivity with decreasing frequency was also observed in studies under atmospheric pressure and is associated with the polarisation of capacitor plates due to ionic contaminations [8][9][10][11][12][13][14][15]. The isothermal pressure behaviour of ε may be portrayed by the pressure analogue of relation (1):…”

“…-The behaviour of dielectric permittivity (ε) when approaching the critical consolute point in binary solutions has been the subject of studies already for nearly 6 decades [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The reason for such a long-standing interest was probably the lack of congruence both among experimental results and between theory and experiment (see [1][2][3][4][5][6][7][8][9] and references therein). This was undoubtedly associated with the weakness of the ε(T ) critical anomaly, comparable to that of the specific heat (c p ∝ (T − T C ) 1−α ), the diameter of the coexistence curve (d ∝ (T − T C ) 1−α ) or the density (ρ ∝ (T − T C ) 1−α ), where T C denotes the critical temperature and α ≈ 0.11 is the critical exponent of specific heat (see [16,17] and references therein).…”

“…The "dielectric regime" in which relation (1) may be valid typically starts from f = 1 MHz whereas f = 1 kHz is often chosen as the low-frequency MW reference [9][10][11][12][13][14][15].…”

“…Up to now, studies on dielectric permittivity in critical solutions were carried out only as a function of temperature, under atmospheric pressure (see [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]) and references therein). In this report we present preliminary experimental studies applying the isothermal, pressure path of approaching the critical consolute point.…”

Annihilation of o-Positronium in the Vicinity of the Critical Mixing Point

“…Many critical properties could be qualitatively predicted when regarding a mixture in the vicinity of critical point as an inhomogeneous one. This attempt was successively used in understanding of critical phenomena of low frequency electric permittivity and conductivity [15][16][17][18][19][20], as well as in nonlinear dielectric effect [21]. It has to be pointed out that formal similarities between critical mixtures and real inhomogeneous mixtures (for example emulsions) are true only very close to the critical point, where concentration fluctuations are long-range and long-living.…”