Critical behavior at the nematic-smectic-A transition in butyloxybenzylidene heptylaniline (4O.7)
學年 71
學期 2
出版（發表）日期 1983-06-01
作品名稱 Critical behavior at the nematic-smectic-A transition in butyloxybenzylidene heptylaniline (4O.7)
作品名稱（其他語言）
著者 Garland, C. W.; Meichle, M.; Ocko, B.M.; Kortan, A. R.; Safinya, C. R.; Yu, L.J.; Litster, J. D.; Birgeneau,R.J.
單位 淡江大學化學學系
出版者 College Park: American Physical Society
著錄名稱、卷期、頁數 Physical Review A (General Physics) 27(6), pp.3234
摘要 High-resolution ac calorimetric, x-ray, and light-scattering measurements have been made on N-[4-(n-butyloxy)benzylidene]-4'-(n-heptyl)aniline (4O.7) near the nematic-smectic-A phase transition. This transition is second order, with a variation in Cp which is well described by a critical exponent α=α'=-0.026 corresponding to the three-dimensional XY model. The longitudinal and transverse correlation lengths exhibit single-power-law divergences over the reduced-temperature range 10-2 to 3×10-5 with exponents ν∥=0.78+/-0.02 and ν⊥=0.65+/-0.02, respectively. The anisotropic hyperscaling relation ν∥+2ν⊥+α=2 is satisfied to within the errors. A dynamical-scaling analysis of light-scattering measurements of the bend-mode director fluctuations with elastic constant K3 yields values for ξ∥ which agree absolutely with the x-ray measurements. Thus the data are all internally consistent, and they appear to exclude all current theories of the nematic-smectic-A transition. It is observed that the overall critical behavior in smectic liquid crystals is sensitive to the width of the nematic range; this may offer an explanation for the apparent nonuniversality of the exponents.
關鍵字
語言 en
ISSN 0556-2791
期刊性質 國外
收錄於 SCI
產學合作
通訊作者 Yu, L.J.
審稿制度
國別 USA
公開徵稿
出版型式 紙本
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