Nematic to smectic-A phase transition

Pershan, P. S.

doi:10.1107/97809553602060000566

International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

pdf | chapter contents | chapter index | related articles

International Tables for Crystallography (2006). Vol. B. ch. 4.4, pp. 464-465 | 1 | 2 |

Section 4.4.7.2. Nematic to smectic-A phase transition

P. S. Pershan^a ^*

^aDivision of Engineering and Applied Science and The Physics Department, Harvard University, Cambridge, MA 02138, USA
Correspondence e-mail: pershan@deas.harvard.edu

4.4.7.2. Nematic to smectic-A phase transition

| top | pdf |

At the time this manuscript was prepared, there was a fundamental discrepancy between theoretical predictions for the details of the critical properties of the second-order nematic to smectic-A phase transition. This has been resolved. W. G. Bouwan & W. H. de Jeu [Phys. Rev. Lett. (1992), 68, 800–803] reported an X-ray scattering study of the critical properties of octyloxyphenylcyanobenzyloxybenzoate in which the data were in good agreement with predictions of the three-dimensional xy model [T. C. Lubensky (1983). J. Chim. Phys. 80, 31–43; J. C. Le Guillou & J. Zinn-Justin (1985). J. Phys. Lett. 52, L-137–L-141]. The differences between this experiment and others that were discussed previously, and which did not agree with theory, are firstly that this material is much further from the tricritical point that appears to be ubiquitous for most liquid-crystalline materials and, secondly, that they used the Landau–De Gennes theory to argue that the critical temperature dependence for the $[{\bf Q}_{\perp}^{4}]$ term in the differential cross section given in equation (4.4.2.7) is not that of the $[c\xi_{\perp}^{4}]$ term but rather should vary as $[[(T - T_{\rm NA})/T]^{-\gamma/4}]$ , where $[\gamma]$ is the exponent that describes the critical-temperature dependence of the smectic order parameter $[|\Psi |^{2}\simeq [(T - T_{\rm NA})/T]^{-\gamma}]$ . The experimental results are in good agreement with the Monte Carlo simulation of the N–S_A transition that was reported by C. Dasgupta [Phys. Rev. Lett. (1985), 55, 1771–1774; J. Phys. (Paris), (1987), 48, 957–970].

References

Birgeneau, R. J., Garland, C. W., Kasting, G. B. & Ocko, B. M. (1981). Critical behavior near the nematic–smectic-A transition in butyloxybenzilidene octylaniline (4O.8). Phys. Rev. A, 24, 2624–2634.Google Scholar

Brisbin, D., De Hoff, R., Lockhart, T. E. & Johnson, D. L. (1979). Specific heat near the nematic–smectic-A tricritical point. Phys. Rev. Lett. 43, 1171–1174.Google Scholar

Davidov, D., Safinya, C. R., Kaplan, M., Dana, S. S., Schaetzing, R., Birgeneau, R. J. & Litster, J. D. (1979). High-resolution X-ray and light-scattering study of critical behavior associated with the nematic–smectic-A transition in 4-cyano-4′-octylbiphenyl. Phys. Rev. B, 19, 1657–1663.Google Scholar

Djurek, D., Baturic-Rubcic, J. & Franulovic, K. (1974). Specific-heat critical exponents near the nematic–smectic-A phase transition. Phys. Rev. Lett. 33, 1126–1129.Google Scholar

Garland, C. W., Meichle, M., Ocko, B. M., Kortan, A. R., Safinya, C. R., Yu, L. J., Litster, J. D. & Birgeneau, R. J. (1983). Critical behavior at the nematic–smectic-A transition in butyloxybenzylidene heptylaniline (4O.7). Phys. Rev. A, 27, 3234–3240.Google Scholar

Kasting, G. B., Lushington, K. J. & Garland, C. W. (1980). Critical heat capacity near the nematic–smectic-A transition in octyloxycyanobiphenyl in the range 1–2000 bar. Phys. Rev. B, 22, 321–331.Google Scholar

Litster, J. D., Als-Nielsen, J., Birgeneau, R. J., Dana, S. S., Davidov, D., Garcia-Golding, F., Kaplan, M., Safinya, C. R. & Schaetzing, R. (1979). High resolution X-ray and light scattering studies of bilayer smectic A compounds. J. Phys. (Paris) Colloq. 40, C3–339–C3–344.Google Scholar

Ocko, B. M., Birgeneau, R. J., Litster, J. D. & Neubert, M. E. (1984). Critical and tricritical behavior at the nematic to smectic-A transition. Phys. Rev. Lett. 52, 208–211.Google Scholar

Sirota, E. B., Pershan, P. S. & Deutsch, M. (1987). Modulated crystalline-B phases in liquid crystals. Phys. Rev. A, 36, 2902–2913.Google Scholar

Sirota, E. B., Pershan, P. S., Sorensen, L. B. & Collett, J. (1985). X-ray studies of tilted hexatic phases in thin liquid-crystal films. Phys. Rev. Lett. 55, 2039–2042.Google Scholar

Sirota, E. B., Pershan, P. S., Sorensen, L. B. & Collett, J. (1987). X-ray and optical studies of the thickness dependence of the phase diagram of liquid crystal films. Phys. Rev. A, 36, 2890–2901.Google Scholar

Thoen, J., Marynissen, H. & Van Dael, W. (1982). Temperature dependence of the enthalpy and the heat capacity of the liquid-crystal octylcyanobiphenyl (8CB). Phys. Rev. A, 26, 2886–2905.Google Scholar

Thoen, J., Marynissen, H. & Van Dael, W. (1984). Nematic–smectic-A tricritical point in alkylcyanobiphenyl liquid crystals. Phys. Rev. Lett. 5, 204–207.Google Scholar

International Tables for Crystallography (2006). Vol. B. ch. 4.4, pp. 464-465