Short time dynamics in the isotropic phase of liquid crystals: the aspect ratio and the power law decay

Optical heterodyne detected optical Kerr effect (OHD-OKE) experiments are used to study the orientational dynamics of the liquid crystal 4 ′-octyl-4-biphenylcarbonitrile (8CB) in the isotropic phase near the isotropic to nematic phase transition. The results are compared to those for three other liq...

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Vydáno v:Chemical physics letters Ročník 366; číslo 1; s. 82 - 87
Hlavní autoři: Cang, Hu, Li, Jie, Fayer, M.D
Médium: Journal Article
Jazyk:angličtina
Vydáno: Amsterdam Elsevier B.V 25.11.2002
Elsevier Science
Témata:
Condensed matter: structure, mechanical and thermal properties
Exact sciences and technology
Liquid crystals
Orientational order of liquid crystals; electric and magnetic field effects on order
Physics
Structure of solids and liquids; crystallography
Exponential distribution
Molecular dynamics
Liquid phase
Experimental study
Aspect ratio
Liquid crystals
Relaxation time
Molecular orientation
Optical Kerr effect
Temperature effects
Saturated aliphatic compound
Heterodyne detection
Benzenic compound
Nitriles
Molecular reorientation
Power law
Organic compounds
Liquid nematic transformation
ISSN:0009-2614, 1873-4448
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Popis
Shrnutí:Optical heterodyne detected optical Kerr effect (OHD-OKE) experiments are used to study the orientational dynamics of the liquid crystal 4 ′-octyl-4-biphenylcarbonitrile (8CB) in the isotropic phase near the isotropic to nematic phase transition. The results are compared to those for three other liquid crystals. The 8CB data display a short time scale temperature independent power law decay and a long time scale exponential decay with a temperature dependence described by Landau–de Gennes theory. The power law exponent is −0.56. Combining this result with previous results for three other liquid crystals [J. Chem. Phys. 116 (2002) 6339; J. Chem. Phys. 116 (2002) 360], it is found that the power law exponent depends linearly on the aspect ratio of the liquid crystal.
ISSN:0009-2614
1873-4448
DOI:10.1016/S0009-2614(02)01542-7