Abstract:
Previous methods for determining the excited state acid-base characteristics of molecules from
kinetic data are applicable only to molecules which undergo dissociation upon excitation. This paper
presents a method of obtaining kinetic data from fluorescence measurements for compounds, which,
upon excitation, take on a proton. The kinetic data so obtained can be used to calculate the excited
state acidity constants of the protonated molecules. Comparison, for two naphthoic acids, of the
results so obtained with data from the spectral method due to Forster and with data from the pH at
which the fluorescence spectrum undergoes a transformation reveals considerable discrepancies:
these are discussed briefly.
