Heat capacity of macro- and nano-systems under gravity near the critical point

A. Alekhin1, B. Abdikarimov1, E. Rudnikov1 and Y. Ostapchuk1

1Physics Department, Kyiv National Taras Shevchenko University, Kyiv, Ukraine

Keywords: critical point, gravity effect, inhomogeneous liquid
property: nonmonotonic dependences of heat capacity
material: dielectrical liquids, binary solutions

The field (height) and temperature dependences of the heat capacity at constant volume Cv of the inhomogeneous substance under gravity field near the critical point have been investigated on the basis of the fluctuation theory of phase transitions (FTPT) and of the behavior of the free energy surface of the system  [1]. On the basis of the FTPT and theory of gravity effect [2] the equations for the heat capacity at constant volume Cv of inhomogeneous system have been derived for the three limiting critical directions (critical isochor, critical isotherm and phase interface). Obtained results have been used for study of heat capacity for small nano-systems near the critical point based on the relation between the system size L and the field variable of field of gravity [3].

It has been for the first time revealed that the heat capacity of inhomogeneous substance has the nonmonotonic temperature and field (height) dependences in the supercritical temperature region (t>0) with the maximums at heights h>0 and h0, h=>0.

The equations for the lines of the extremes of the height and temperature dependences of the heat capacity at constant volume have been obtained on the basis of the linear model of parametric equation of state.

These conclusions correspond to the experimental studies of the heat capacity in small nano- systems under the terrestrial conditions [4] and also under the cosmic conditions of micro-gravity [5].

  1. A.D. Alekhin, E.G. Rudnikov, UPhJ, 47 (8), 745 (2002)

  2. A.D. Alekhin, M.P. Krupsky, A.V. Chalyj, JETPh, 63, (4) 1417 (1972)

  3. M.E. Fisher, M.N. Barber, Phys. Rev. Lett., 28, 1516 (1972).

  4. V.P. Voronov, V.M. Buleyko, JETPh, 113, (3), 1071 (1998).

  5. J.A. Lipa, M. Goleman D.A. Striker , J. Low. Temp. Phys. 124 (3-4), 443 (2001)

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