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Thermodynamic functions using the coefficient of volume expansion (α) of a system, a number of thermoacoustic and anharmonic parameters such as the isochoric temperature coefficient of internal pressure (X), isochoric temperature coefficient of volume expansivity (X'), reduced compressibility (β∼), reduced volume (V∼), isothermal microscopic Gruneisen parameter (Γ), fractional free volume (f), and Sharma parameter (So) can be investigated. The temperature dependence of these parameters gives a basic understanding about the intermolecular interactions in general. These studies also can applied to a solute in dilute solutions. In the present study these different parameters have been determined using volumetric measurements in the case of a liquid crystal, namely, 4,4'-dibutoxy azoxy benzene (HPOAB), which is a typical liquid crystal with a nearly linear structure, in dilute solutions at different temperatures. Variations in various parameters with respect to temperature are discussed in the light of the results obtained. The variation of the properties is analyzed and discussed in this article. [ABSTRACT FROM AUTHOR]

The determination of excited state electric dipole moment through solvatochromic shifts of two Exalite dyes, namely, E-392A, E-398 have been carried out using fluorescence shifts and have been found to be less than those calculated through absorption shifts. It is felt that the one calculated using shifts in emission are more reliable. The results are presented and discussed. A qualitative estimate of the orientation of dipole moments in ground and excited state are also presented and discussed. [ABSTRACT FROM AUTHOR]

A new method is proposed to estimate the polarizability (αe) of a molecule in an excited state using solvatochromic shift measurements and McRae's equation. In the earlier methods the contribution due to polarizability was not considered. In view of this, the proposed method is also expected to give a better estimation of excited state electric dipole moment (μe) and the (θ) angle between excited and ground state electric dipole moments, μe and μg apart from giving values of polarizability of the molecules in the excited state. This method has been applied in the case of the La band of p-nitro aniline and the results for all the parameters are found to be satisfactory and of right order in comparison with that reported in literature. [ABSTRACT FROM AUTHOR]