Time dependence of dissociation in the excited state of β-naphthol

Fluorescence decay measurements were used to investigate the mechanism of the acid dissociation of β-naphthol in the excited singlet state. The solutions of the differential equations involved show that the naphthol fluorescence should decay exponentially while the naphtholate ion decay should involve a difference of exponentials. Comparison between the calculated and the measured decay functions indicates that about 20% of the acid dissociation takes place before the thermalized equilibrium excited state, ¹S, is reached.