Chemical Physics Connection Self quenching of 1 -naphthol. between time-resolved and steady-state measurements

Abstract The photochemistry of I-naphthol following its electronic excitation in aqueous solution was investigated by a single-photon counting apparatus. It was found that following the proton dissociation the excited naphtholate anion decays non-exponentially withar-"* dependence over time. This we attribute to a self-quenching reaction of the naphtholate anion by its geminate proton. The quenching rate on contact is 3.5 X 10" s-'. We also found that some of the protons interact adiabatically with a geminate recombination rate in D20 of 8 X 10' s-'. The time-dependent escape probability of the naphtholate ion-pair was sampled by carrying out the experiment in presence of a proton scavenger. We show that the leading term in the ultimate scavenging probability is given by the time integral of the homogeneous scavenging rate of the isolated pair at relatively long times following its creation