Spectra of nonlinearly excited luminescence in nucleoside triphosphates

Spectra of two-photon-excited fluorescence of crystalline nucleoside triphosphates have been measured. There is a correlation in the shape of the fluorescence of nucleoside molecules containing the same number of aromatic rings. The measured duration of the fluorescence is ~10^–8 s. A fine structure is observed in the spectrum of the two-photon-excited fluorescence. It is attributed to vibrational levels of the electronic ground state.