The European Physical Journal E

, Volume 17, Issue 3, pp 345–351 | Cite as

Effect of shape anisotropy on the phase diagram of the Gay-Berne fluid

  • Pankaj Mishra
  • Jokhan Ram
Original Article


We have used the density functional theory to study the effect of molecular elongation on the isotropic-nematic, isotropic-smectic A and nematic-smectic A phase transitions of a fluid of molecules interacting via the Gay-Berne intermolecular potential. We have considered a range of length-to-width parameter 3.0 ⩽ x0 ⩽ 4.0 in steps of 0.2 at different densities and temperatures. Pair correlation functions needed as input information in density functional theory are calculated using the Percus-Yevick integral equation theory. Within the small range of elongation, the phase diagram shows significant changes. The fluid at low temperature is found to freeze directly from isotropic to smectic A phase for all the values of x0 considered by us on increasing the density while the nematic phase stabilizes in between isotropic and smectic A phases only at high temperatures and densities. Both isotropic-nematic and nematic-smectic A transition density and pressure are found to decrease as we increase x0. The phase diagram obtained is compared with computer simulation result of the same model potential and is found to be in good qualitative agreement.


64.70.Md Transitions in liquid crystals 61.30.Cz Molecular and microscopic models and theories of liquid crystal structure 61.30.Dk Continuum models and theories of liquid crystal structure 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    P.G de Gennes, J. Prost, The Physics of Liquid Crystals (Clarendon, Oxford, 1993)Google Scholar
  2. 2.
    J.G. Gay, B.J. Berne, J. Chem. Phys. 74, 3316 (1981).CrossRefGoogle Scholar
  3. 3.
    G.R. Luckhurst, P.S.J. Simmonds, Mol. Phys. 80, 233 (1993).Google Scholar
  4. 4.
    E. de Miguel, L.F. Rull, M.K. Chalam, K.E. Gubbins, E.V. Swol, Mol. Phys. 72, 593 (1991).Google Scholar
  5. 5.
    E. de Miguel, L.F. Rull, M.K. Chalam, K.E. Gubbins, Mol. Phys. 74, 405 (1991).Google Scholar
  6. 6.
    G.R. Luckhurst, R.A. Stephens, R.W. Phippen, Liq. Cryst. 8, 451 (1990).Google Scholar
  7. 7.
    E. de Miguel, E. Martin del Rio, J.T. Brown, M.P. Allen, J. Chem. Phys. 105, 4234 (1996). CrossRefGoogle Scholar
  8. 8.
    M.P. Allen, J.T. Brown, M.A. Warren, J. Phys. Condens. Matter 8, 9433 (1996).CrossRefGoogle Scholar
  9. 9.
    J.T. Brown, M.P. Allen, E. Martin del Rio, E. de Miguel, Phys. Rev. E 57, 6685 (1998).CrossRefGoogle Scholar
  10. 10.
    M.A. Bates, G.R. Luckhurst, J. Chem. Phys. 110, 7087 (1999).CrossRefGoogle Scholar
  11. 11.
    E. de Miguel, E. Martin del Rio, J. Chem. Phys. 118, 1852 (2003).CrossRefGoogle Scholar
  12. 12.
    E. de Miguel, Mol. Phys. 100, 2449 (2002).CrossRefGoogle Scholar
  13. 13.
    L. Longa, G. Cholewiak, R. Terbin, G.R. Luckhurst, Eur. Phys. J. E 4, 51 (2001).Google Scholar
  14. 14.
    E. Velasco, A.M. Somoza, L. Mederos, J. Chem. Phys. 102, 8107 (1995).CrossRefGoogle Scholar
  15. 15.
    E. Velasco, L. Mederos, J. Chem. Phys. 109, 2361 (1998).CrossRefGoogle Scholar
  16. 16.
    R.C. Singh, J. Ram, Y. Singh, Phys. Rev. E 65, 031711 (2002).CrossRefGoogle Scholar
  17. 17.
    R.C. Singh, J. Ram, Physica A 326, 13 (2003).Google Scholar
  18. 18.
    P. Mishra, J. Ram, Y. Singh, J. Phys. Condens. Matter 16, 1695 (2004).CrossRefGoogle Scholar
  19. 19.
    Y. Singh, Phys. Rep. 207, 351 (1991).CrossRefGoogle Scholar
  20. 20.
    W.L. McMillan, Phys. Rev. A 4, 1238 (1971).CrossRefGoogle Scholar
  21. 21.
    R.C. Singh, J. Ram, Y. Singh, Phys. Rev. E 54, 977 (1996)CrossRefGoogle Scholar

Copyright information

© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2005

Authors and Affiliations

  • Pankaj Mishra
    • 1
  • Jokhan Ram
    • 1
  1. 1.Department of PhysicsBanaras Hindu UniversityVaranasiIndia

Personalised recommendations