A study on refractive index, orientational order parameter and distribution function in the nematic phase of a nematogenic compound

2017 ◽  
Vol 646 (1) ◽  
pp. 176-182
Author(s):  
D. GopalaKrishna ◽  
G. Bagyalakshmi ◽  
T. Demappa
Keyword(s):  
Refractive Index ◽  
Distribution Function ◽  
Order Parameter ◽  
Nematic Phase ◽  
Orientational Order ◽  
Orientational Order Parameter

Optical properties of a liquid crystal with small ordinary and extraordinary refractive indices and small optical anisotropy

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
J. Kędzierski ◽  
K. Garbat ◽  
Z. Raszewski ◽  
M. Kojdecki ◽  
K. Kowiorski ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Optical Anisotropy ◽  
Order Parameter ◽  
Orientational Order ◽  
Refractive Indices ◽  
Orientational Order Parameter ◽  
Unknown Density ◽  
Abbe Refractometer

AbstractOptical properties of a nematic liquid crystal with small refractive index and small birefringence were studied. The ordinary and extraordinary refractive indices and birefringence were measured as functions of temperature by using an Abbe refractometer and wedge nematic cells. From values of these indices the nematic orientational order parameter was calculated by using several methods and corresponding mathematical models. Kuczyński et al. method was found to be suitable for determining the order parameter also for materials featuring small ordinary refractive index, with unknown density.

scholarly journals Study of Molecular Polarizabilities and Orientational Order Parameter in the Nematic Phase of 6.O12O.6 and 7.O12O.7

2011 ◽  
Vol 01 (04) ◽  
pp. 167-174 ◽  
Author(s):  
Parameswara Rao Alapati ◽  
D. Bhuyan ◽  
D. Madhavi Latha ◽  
P. Pardhasaradhi ◽  
V. G. K. M. Pisipati ◽  
...  
Keyword(s):  
Order Parameter ◽  
Nematic Phase ◽  
Orientational Order ◽  
Orientational Order Parameter ◽  
Molecular Polarizabilities

Studies on binary mixtures of 4-pentyloxy-4′-cyanobiphenyl with three 4, 4′-di(alkoxy)azoxybenzenes

2010 ◽  
Vol 18 (2) ◽  
Author(s):  
B. Jaishi ◽  
P. Mandal ◽  
R. Dąbrowski
Keyword(s):  
Binary Mixtures ◽  
Order Parameter ◽  
Nematic Phase ◽  
Transition Point ◽  
Orientational Order ◽  
Smectic Phase ◽  
Refractive Indices ◽  
Orientational Order Parameter ◽  
Polarizability Anisotropy ◽  
Good Agreement

AbstractEighteen binary mixtures of 4-pentyloxy-4′-cyanobiphenyl (5OCB) and 4, 4′-di(alkoxy)azoxybenzenes (nOAB) with n = 5, 6, and 7 at different concentrations have been studied in detail. Over a wide concentration range, induced SmA phase was observed in all the mixtures except in one. In most of the mixtures, the refractive indices no, ne, and Δn lie between the values of pure components. The optical birefringence of the mixtures is found to decrease non-additively with concentration. The molecular polarizability anisotropy and the orientational order parameter <P2> of the mixtures were calculated. Nature of variation of polarizability anisotropy with concentration is similar to that of Δn. In allmixtures <P2> is more in smectic phase than in nematic phase and it also shows non-additive behaviour. Observed <P2> values of the mixtures were compared with McMillan’s and Maier-Saupe theoretical values and good agreement is found in some mixtures. The transition temperatures obtained by fitting <P2> data to McMillan’s theory agree with the observed values within a few degrees. Ratio of elastic constants K33 and K11 is determined for mixtures having nematic phase and found to diverge at TNA transition point.

scholarly journals Molecular ordering in the high-temperature nematic phase of an all-aromatic liquid crystal

Soft Matter ◽  
2016 ◽  
Vol 12 (8) ◽  
pp. 2309-2314 ◽  
Author(s):  
Francesco Vita ◽  
Maruti Hegde ◽  
Giuseppe Portale ◽  
Wim Bras ◽  
Claudio Ferrero ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
High Temperature ◽  
Theoretical Prediction ◽  
Order Parameter ◽  
Nematic Phase ◽  
Orientational Order ◽  
Strong Tendency ◽  
Molecular Layering ◽  
Orientational Order Parameter ◽  
Molecular Ordering

The high-temperature nematic phase of all-aromatic lath-like 2,6-biphenyl naphthalene (PPNPP) exhibits a surprisingly strong tendency towards molecular layering (i.e.SmA-like cybotaxis) and an orientational order parameter slightly deviating from Maier–Saupe theoretical prediction.

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