Effect of molecular environment and of excitation energy on electron photoejection from monophenylphosphate

Abstract

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.