Molecular order variation

Fukui functions and other response properties can also be derived from the one-electron Kohn-Sham orbitals of the unperturbed system [14]. Following Equation 12.9, Fukui functions can be connected and estimated within the molecular orbital picture as well. Under frozen orbital approximation (FOA of Fukui) and neglecting the second-order variations in the electron density, the Fukui function can be approximated as follows [15] ... 

This interpretation is based on the fact that the variation of the overall charge which occurs when the metal complex undergoes a redox process influences the number of solvent molecules surrounding the complex (which are hence electrostatically orientated), as well as the number of solvent molecules which form hydrogen bonds with the complex. The change in the number of solvent molecules near the metal complex can be translated into an increase or decrease of the molecular order of the entire system and, hence, into an increase or decrease of entropy. 

Liquid crystals are classified into lyotropic and thermotropic crystals depending on the way in which the mesomorphic phase is generated. Lyotropic liquid-crystalline solvents are formed by addition of controlled amounts of polar solvents to certain amphiphilic compounds. Thermotropic liquid-crystalline solvents, simply obtained by temperature variations, can be further classified into nematic, smectic, and cholesteric solvents depending on the type of molecular order present. Liquid crystals are usually excellent solvents for other organic compounds. Nonmesomorphic solute molecules may be incorporated into liquid-crystalline solvents without destruction of the order prevailing in the liquid-crystalline matrix (Michl and Thulstrup, 1986). Ordered solvent phases such as liquid crystals have also been used as reaction media, particularly for photochemical reactions (Nakano and Hirata, 1982). 

The constant Vq may be set equal to zero. In a point of equilibrium, the first derivatives are equal to zero, while those higher than the second-order variations are neglected (this is the meaning of the term small molecular vibrations ). 

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