Advertisement

The Nematic and Smectic-A1 Phases in DB7NO2: High Resolution X-Ray Study and Synthesis

  • C. R. Safinya
  • L. Y. Chiang
Part of the NATO ASI Series book series (NSSB, volume 166)

Abstract

We report a high resolution x-ray study of the fluctuations in the nematic and smectic-A1 phases in DB7NO2. As a function of decreasing temperature, the fluctuations evolve from an incommensurate region, through an intermediate region of coexisting (competing) incommensurate and smectic-C̃ fluctuations, to a region dominated by pretransitional smectic-Ã fluctuations which exhibit a phase lock-in smectic Ã1-smectic-Ã transition. This behavior directly confirms the current theoretical description of the smectic-Ã and smectic-C̃ phases as alternatives to the incommensurate phase. In DB7NO2, although the average structure of the smectic-Ã phase appears to be consistent with earlier findings, high resolution x-ray work reveals additional weaker (possibly satellite) peaks indicating a more complicated underlying structure. Finally, we outline a novel new synthetic route for preparation of high purity samples of DB7NO2 in large quantities.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    A. M. Hardouin, M. F. Levelut, G. Archard, and G. Sigaud, J. Chim. Phys. 80, 53 (1983); C. C. Huang, S. C. Lien, S. Dumrograttana, and L. Y. Chiang, Phys. Rev. A30, 965 (1984).CrossRefGoogle Scholar
  2. 2.
    K. K. Chan, P. S. Pershan, L. B. Sorenson, and F. Hardouin, Phys. Rev. Lett. 54, 1694 (1985).ADSCrossRefGoogle Scholar
  3. 3.
    B. R. Ratna, R. Shashidhar, V. N. Raja, Phys. Rev. Lett. 55, 1476 (1985).ADSCrossRefGoogle Scholar
  4. 4.
    J. Prost and P. Barois, J. Chim. Phys. 80, 65 (1983); J. Prost, Advances in Physics, 33, 1–46 (1984).CrossRefGoogle Scholar
  5. 5.
    J. Wang and T. C. Lubensky, J. Phys. 45, 1653 (1984).CrossRefGoogle Scholar
  6. 6.
    R. J. Birgeneau, C. W. Garland, G. B. Kasting, and B. M. Oco, Phys. Rev. A24, 2624 (1981).ADSCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • C. R. Safinya
    • 1
  • L. Y. Chiang
    • 1
  1. 1.Corporate Research Science LaboratoriesExxon Research and Engineering CompanyAnnandaleUSA

Personalised recommendations