Classical theory is used to derive the optical parameters (refraction, extinction coefficient, reflectivity, rotation, and ellipticity) of a macroscopic sample containing aggregated monomer chemical units. The samples considered are dilute solutions of molecular aggregates or polymer molecules, and molecular crysstals. In this theory, each electronic transition of a monomer is represented by an electronic and a magnetic oscillator with complex polarizabilities which are evaluated empirically from the absorption and optical activity of unaggregated monomers. The complex refractive index for a refracted wave in the sample is obtained from Maxwell's equations and the electric and magnetic polarizations, taking into account Coulomb interactions between the oscillators. The optical parameters at any frequency are evaluated from the refractive indices for linearly or circularly polarized light. The results agree, in the same order of approximation, with those derived by several quantum theories. Sum rules are derived for the conservation of the monomer oscillator strengths and rotational strengths in the aggregates.

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A theoretical classical model is developed to predict the absorption and refraction of an aggregate of monomer units (a molecular aggregate, molecular crystal, or polymer) at any frequency. The monomers are treated as having complex electronic polarizabilities whose frequency dependence is determined by the absorption bands of the isolated monomers. Polarizations in the aggregate induced by incident light are modified by Coulombic interactions between the monomers. No first-order approximation is involved as in exciton theory. The molar extinction coefficient and molar refraction are obtained from normal mode polarizabilities found by solving an eigenvalue problem. The predicted absorption spectra agree (to first order in interaction energy) with exciton theory in the limit of weak coupling, with the hypochromism theory of Tinoco and Rhodes, and (for a classical oscillator model) with exciton theory for strong coupling. The oscillator strength sum rule is obeyed. The predicted spectrum of a pair of dyelike monomers is illustrated for the cases of weak, intermediate, and strong coupling.

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Generator columns packed with a solid support and loaded with a liquid organic phase make it possible to rapidly and conveniently equilibrate water with the organic phase. By coupling the generator column to an extractor column for high pressure liquid chromatographic analysis of the aqueous solution, errors from surface adsorption and loss to the atmosphere are avoided. Using this method, the mean values and confidence limits at a 95 percent confidence level of the aqueous solubility, S, and the octanol-water partition coefficient, P, of n-propylbenzene at 25°C were found to be S = (4.32 ± 0.02) X 1O-4 M and log P = 3.720 ± 0.003.