Electronic Susceptibilities of Liquid Crystals

Trans-Cis Singlet-Triplet Crossing Nonradiative Relaxations 

More recently, these nonlinear absorption processes have been actively investigated in the contexts of nonlinear transmission and optical limiting of ultrashort laser pulses. A detailed discussion will be given in Chapter 12. 

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The magnitudes of the various tensorial components of the nonlinear susceptibilities of liquid crystals are determined fundamentally by their electronic stmcture. Since... 

D. M. Walha. M. a Roe, N. A. dark. R. Shao. K. M. Johnson. M. O. Robinson. J. Y. Un. and D. Doroski. An approach to the design of ferroelectric liquid crystals with large second order electronic nonlinear optical susceptibility. MoL Cryst Liq. CrysL J98 51 (1991). 

These examples involve pendant groups that interact with each other. There are, of course, several examples of polymers containing pendant chromophores, particularly as liquid crystal mesogens, that have been investigated as nonlinear optical matoials. In these materials, the electronic interaction between chromophores does not generally contribute to the material s nonlinear optical susceptibility. ... 

Although a stiff chain conformation of polyaniline in solution in sulfuric acid is consistent with the conclusions inferred from the magnetic susceptibility data [46], the absence of evidence of liquid crystallinity for polyaniline in sulfuric acid suggests a more flexible chain conformation. On the other hand, the strong interchain electron transfer interactions inherent to n-conjugated polymers may lead to crystallization (and precipitation) rather than liquid crystal formation. 

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