The rate constants of the internal, radiative, and intercombination conversion, as well as photoprotonation centers, in the 1-naphthol molecule were estimated through quantum-chemical calculation by the PNDO (partial neglect of differential overlap) method. It has been found that besides the processes of quenching due to intercombination conversion, the possibility of protonation of the molecule in the excited state should be taken into account. Protonation centers for the neutral and anion forms of 1-naphthol were determined. Possible values of the acidity constant of the 1-naphthol molecule in the excited state (рK*) range from 0.4 to 2.8.