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Liquid Crystals. Iam-Choon Khoo
Читать онлайн.Название Liquid Crystals
Год выпуска 0
isbn 9781119705796
Автор произведения Iam-Choon Khoo
Издательство John Wiley & Sons Limited
More generally, one can write Eq. (3.33) as
where
3.4.2. Equilibrium Temperature and Order Parameter Dependences of Refractive Indices
The two principal refractive indices n⊥ and n|| of a uniaxial liquid crystal and the anisotropy n|| − n⊥ have been the subject of intensive studies for their fundamental importance in the understanding of liquid crystal physics and for their vital roles in applied electro‐optic devices. Since the dielectric constants (ε⊥ and ε||) enter directly and linearly into the constitutive equations (Eqs. (3.30a)–(3.30c)), it is theoretically more convenient to discuss the fundamentals of these temperature dependences in terms of the dielectric constants.
From Eq. (3.34) for the local field
(3.35)
where
The dielectric constant
(3.36)
and
(3.37)
From these considerations and from observations by deJeu and Bordewijk [13] that
(3.38)
and
(3.39)
we can write ε|| and ε⊥ as
and
respectively, where Kl and Kt are the values of