Solvent Effects on the nπ* and ππ* Absorption Intensities of Some Organic Molecules

Abstract

Abstract Recently proposed experimental and theoretical expressions for the molecular electronic oscillator strength in a solution (J. Chem. Phys., 83, 1546 (1985)) have been succesfully applied to the spectral data of some nonpolar and polar organic molecules (benzoquinones, ketones, nitroalkanes, β-carotene, and substituted benzenes). In an application of the theoretical expression, the transition moment of a nonpolar solute molecule in various solvents was assumed to be approximately constant, while that of a polar solute molecule was developed on the assumptions of a first-order perturbation of the wave function and a Block–Walker reaction field. The ratio of the oscillator strength in a solution to that either in a vapor or a specified solvent was computed from both experimental data and theoretically from the transition moments. The results of the two computational modes are, generally, in good agreement for the range of compounds studied.