Linear Interaction Energy terms Links

Properties of the microenvironment of soluble and cross-linked polymers were studied by the shift of bands in the electron spectra of solvatochromic reporter molecules embedded in polymer chains. Generally, the charge-transfer (CT) absorption spectra and emission spectra of a number of compounds were used to correlate solute-solvent interactions with physical and chemical properties of interest. The energy of the band maxima of these chromophores is quite solvent sensitive and is linearly correlated with empirical solvent polarity parameters. The observed shift of the maximum of the solvatochromic reporter embedded in the polymer chains, compared with a low-molecular weight analog in the same solvent, was interpreted in terms of a change in the polarity of the microenvironment of the polymer in solution. 

Such a form of quasi-equilibrium distribution takes place due to the fact of the availability of two invariants of motion. In Equation 25 parameters a and p linked to the operators Hz and Hss are thermodynamically conjugative parameters for the Zeeman energy and the energy of spin-spin interactions respectively. We can expand the exponent in Equation 25 in jxjwers of xT-Lz and f Hss and keep only the linear terms. As we shall see later such a linearization corresponds to the high temperature approximation. In the linear approximation in x Hz and Hss, the density matrix is reduced to... 

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