Fluorescence of the purine and pyrimidine bases of the nucleic acids in neutral aqueous solution at 300 degrees K.

Fluorescence of adenine, guanine, cytosine, and uracil at room temperature in neutral aqueous solution has been detected by means of a digital signal accumulation technique. Corrected emission and excitation spectra are presented and compared with low-temperature data. The quantum yields are, respectively, 2.6 x 10(-4), 3.0 x 10(-4), 0.8 x 10(-4), and 0.5 x 10(-4) when the bases are excited at their low-energy absorption maxima.