PHOTOIONIZATION OF CRYSTAL VIOLET IN AQUEOUS SOLUTION

Abstract— Laser flash photolysis studies were carried out on a triphenylmethane dye, crystal violet (CV⁺), at 248 nm in aqueous solutions. The results show that CV⁺ undergoes photoionization and the resulting transients CV^-2+, hydrated electrons (e^-_aq) and CV⁺ radical formed by the reaction of e^-_aq with CV⁺ have been characterized. Studies using suitable scavengers were done to support the characterization of the transient species. Laser intensity effects show that the ionization is biphotonic. Two mechanisms are proposed to explain the observed photoionization involving higher excited singlet state and/ or another long-lived excited state of the dye.