Gibbs Density Surface of Water and Steam: 2nd Debate on the Absence of Van Der Waals’ “Critical Point”

DOI: 10.4236/ns.2014.66041   PDF   HTML   XML   4,129 Downloads   5,981 Views   Citations


A revised phase diagram for water shows three distinct fluid phases. There is no continuity of liquid and gas, and no “critical point” on Gibbs’ density surface as hypothesized by van der Waals. A supercritical colloidal mesophase bounded by percolation transition loci separates supercritical liquid water and gas-phase steam. The water phase is bounded by a percolation transition (PA) of available volume, whereas steam is bounded by the loci of a percolation transition (PB) at a density whereupon a bonded molecular cluster suddenly percolates large distances. At the respective percolation densities, there is no barrier to nucleation of water to steam (PA) or steam to water (PB). Below the critical temperature, the percolation loci become the metastable spinodals in the two-phase coexistence region. A critical divide is defined by the interception of PA and PB the p-T plane. Critical parameters are obtainable from slopes and intercepts of pressure-density supercritical isotherms within the mesophase. The supercritical mesophase is a fourth equilibrium state besides ice, water and steam. A thermodynamic state function rigidity (dp/dρ)T defines a distinction between liquid and gas, and shows a remarkable symmetry due to an equivalence in number density fluctuations, arising from available volume and molecular clusters, in liquid and gas respectively. Following an earlier debate in these pages [“Fluid phases of argon: A debate on the absence of van der Waals’ critical point” Natural Science 5 (2) 194-206 (2013)], we here report further debate on a science of criticality applied to water and steam (APPENDIX 1).

Share and Cite:

Woodcock, L. (2014) Gibbs Density Surface of Water and Steam: 2nd Debate on the Absence of Van Der Waals’ “Critical Point”. Natural Science, 6, 411-432. doi: 10.4236/ns.2014.66041.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Glasser, L. (2004) Water, Water, Everywhere: Phase Diagrams of Ordinary Water Substance. Journal of Chemical Education, 81, 414-418.
[2] Guillot, B. (2002) A Reappraisal of What We Have Learned during Three Decades of Computer Simulations of Water. Journal of Chemical Education, 101, 219-260.
[3] Chaplin, M. (2013) Water Structure and Science.
[4] Van der Waals, J.D. (1873) Over de Continuiteit van den Gas-en Vloeistoftoestand (On the Continuity of the Gas and Liquid State). Ph.D. Thesis, University of Leiden, Leiden.
[5] Binney, J.J., Dowrick, N.J., Fisher, A.J. and Newman, M.E.J. (1995) The Theory of Critical Phenomena: An Introduction to the Renormalization Group. Oxford Science Publications, Oxford.
[6] Wilson, K.G. and Nobel Lecture (1993) The Renormalization Group and Critical Phenomena. December 8 1982. In: Ekspang, G., Ed., Nobel Lectures, Physics 1981-1990, World Scientific Publishing Co., Singapore.
[7] Woodcock, L.V. (2012) Thermodynamic Description of Liquid State Limits. The Journal of Physical Chemistry B, 116, 3735-3744.
[8] Woodcock, L.V. (2013) Observations of a Liquid-Gas Critical Coexistence Line and Supercritical Mesophase Bounds from Percolation Transition Loci. Fluid Phase Equilibria, 351, 25-33.
[9] Woodcock, L.V. (2013) Gibbs Density Surface of Fluid Argon: Revised Critical Parameters. International Journal of Thermophysics, 34, 1411-1416.
[10] Gibbs, J.W. (1873) A Method of Representation of the Thermodynamic Properties of Substances by Means of Surfaces. In: Collected Works of J. Willard Gibbs, Longmans Green and Co, New York, 1928, Chapter 1: Original Publication: Trans. Conn. Acad. Arts Sci., 2, 382.
[11] Wagner, W. and Kretzschmar, H.-J. (2008) IAPWSIF’97 International Steam Tables: Properties of Water and Steam. Springer-Verlag, Berlin.
[12] Bernal, J.D. (1964) The Bakerian Lecture 1962, The Structure of Liquids. Proceedings of the Royal Society (London) A 280, 299-322.
[13] Widom, B.J. (1972) Phase Transitions and Critical Phenomena. In: Domb, C. and Green, M.S., Eds., Phase Transitions and Critical Phenomena, Vol. 2, Academic Press, Waltham.
[14] Brazhkin, V.V., Fomin, Y.-D., Lyapin, A.G., Ryzhov, V.N. and Tsiok, E.N. (2011) Widom line for the Liquid-Gas Transition in Lennard-Jones System. The Journal of Physical Chemistry B, 115, 14112-14115.
[15] Simeoni, G.G., Bryk, T., Gorelli, F.A., Krisch, M., Ruocco, G., Santoro, M. and Scopigno, T. (2010) The Widom Line as the Crossover between Liquid-Like and Gas-Like Behaviour in Supercritical Fluids. Nature Physics, 6, 503-507.
[16] Brazhkin, V.V., Fomin, Yu.D., Lyapin, A.G., Ryzhov, V.N. and Trachenko, K. (2012) Two Liquid States of Matter: A Dynamic line on a Phase Diagram. Physical Review E, 85, 031203.
[17] Gopal, E.S.R. (2000) Critical Opalescence. Resonance, 5, 37-45.
This prevailing explanation of critical opalescence as reviewed by Gopal requires molecular fluctuations or Brownian motion, according to the theories of Einstein and Smoluchowski. It now seems likely that the effect may have little to do with molecular level fluctuations directly, and that there is a simpler explanation as Tyndall scattering which occursdue to the colloidal dispersion nature of the mesophase.
[18] Reif-Acherman, S. (2003) History of the Law of Rectilinear Diameters. Quimica Nova, 33, 2003-2013.
[19] He, S.N. and Attard, P. (2005) Surface Tension of a Lennard-Jones Liquid under Supersaturation. Physical Chemistry Chemical Physics, 7, 2928-2935.
[20] Shamsundar, N. and Lienhard, J.H. (1993) Equations of State and Spinodal Lines—A Review. Nuclear Engineering and Design, 141, 269-287.
[21] Widom, B.J. (1963) Some Topics in the Theory of Liquids. The Journal of Chemical Physics, 39, 2808.
[22] Landau, L.D. and Lifshitz, E.M. (1958) Statistical Physics. Pergamon, London.
[23] Woodcock, L.V. (2013) Fluid Phases of Argon: A Debate on the Absence of van der Waals’ Critical Point. Natural Science, 5, 194-206.

comments powered by Disqus

Copyright © 2020 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.