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The influence of temperature and of various solvents on fluorescence and electron ejection has been studied using monophenylphosphate. Heavy atom quenching experiments with Cs+ ions and the temperature dependence observed for the system show that electrons are not only emitted from the thermalized singlet state of aqueous monophenylphosphate (Q= 0.02 for T= 30°C and pH = 8.2) but probably also during relaxation prior to fluorescence (Q= 0.008). The significant decrease in fluorescence at higher excitation energies can be satisfactorily explained by an increase in photodetachment of e–aq or H according to the pH of the solution (reaching 0.23 at pH 8.2). From the results it was concluded that electron ejection occurs via an intermediate state which has very similar properties to c.t.t.s. states observed in the spectroscopy of inorganic anions.

The dependence of the fluorescence quantum yield, QF, on the energy of the exciting light was examined for a number of aromatic amines (aniline, N,N-dimethylaniline, 2-phenylethylamine, etc.) in various polar and non-polar solvents down to 200 nm. QF of aniline is constant throughout the first absorption system but decreases when the excitation reaches the second band. This effect is most pronounced in hydrocarbon solutions but small in polar solvents capable of forming hydrogen bonds, with the only exception being water. For N,N-dimethylaniline a wavelength dependence of QF is observed only in aqueous solutions. Concomitant to the QF decrease the H2 evolution in hydrocarbons and electron ejection in water increase. These effects are also observed for solutions of 2-phenylethylamine and are explained by the formation of weak intramolecular complexes. A further pathway, characteristic of the benzoic ring, is assumed to be responsible for the wavelength dependence of protonated anilines. The derived deactivation pattern is of general validity for simple polar aromatics.

The dependence of the fluorescence quantum yield Q(F) on the excitation wavelength (λexc) was studied for phenol, anisole, p-cresol, p-methylanisole, 3,5-dimethylphenol and 2,4,6-trimethylphenol in polar and apolar solvents. All the systems investigated, with the exception of anisole and p-methylanisole exhibit a marked decrease in Q(F) at lower λexc values in hydrocarbon solvents. Further it was established that in this case enhanced photochemical cleavage of the OH bond is mainly responsible for this effect. Owing to the formation of H-bonds this dependence diminishes in polar, strongly associating solvents like alcohols and ethers, but not in water.