8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P2.10Tue 611:23-14:00Equation of state for water in the small compressibilityregionVitaliy Bardik, 1 Dmitry Nerukh, 2 Evgen Pavlov, 1 and Igor Zhyganiuk 31 Kiev Taras Shevchenko University, Pr. Glushkova, 4, 03127, Kiev, Ukraine2 Aston University, Birmingham, United Kingdom3 Odessa Mechnikov National University, Odessa, UkraineDespite an essential progress achieved during the last decades in the theoretical and experimentaldescription of the equations of state for dense fluids [1-4], an equation describing the thermodynamicsin a wide interval of pressure and temperature, including the stability boundaries, still remainsto be developed. In our study we consider the problem of the statistical mechanic foundationof the equation of state (EOS) of dense fluids within the framework of the generalized approach[5]. A variant of the thermodynamic perturbation theory based on the scaling transformation ofthe partition function has been applied to the functional expansion of the free energy. We developa new variant of the thermodynamic perturbation theory in which a reference thermodynamic state(P0, V0, T) is specified rather than a reference system. Various modifications of the EOS havebeen derived for a number of simple model potentials on the basis of the free energy functionalseries at a certain choice of small expansion parameters. We considered the derivation of the waterEOS in the high densities limit for the realistic potential model, like the Lennard-Jones potential,and in the framework of short range potentials such as the Sutherland and Katz models. A specialattention is paid to an improved version of the Stillinger-David polarisation potential [6]. Aneffective potential that takes into account the influence of the H-bonds has been constructed. [1].Ch. Tegeler, R. Span, W. Wagner, J. Phys. Chem. Ref. Data, 28, 779, (1999). [2]. W. Wagner,A. Pruss. J. Phys. Chem. Ref. Data, 31, 2, 387-535, (2002). [3]. L. E. Fried, W. M. Howard.J. Chem. Phys. 109, 7338, (1998). [4]. U. Setzmann, W. Wagner. J. Phys. Chem. Ref. Data,20(6), 1061-1151, (1991). [5]. V. Yu. Bardik, et al. Journal of Molecular Liquids, to be published,(2011). [6]. I. V. Zhyganiuk. Ukr. Journal of Physics, 56, 225, (2011).10