[Sensibilized dimer luminescence of singlet molecular oxygen in solutions]

With the use of mechanical phosphoroscope the "universal" delayed emission has been found in aerobic solutions of different sensitizers in CCl4. The spectrum of this emission has the main maximum at 703 nm. The luminescence intensity is proportional to the square of the intensity of the exciting light. Removal of oxygen or addition of 10% of acetone led to disappearance of the luminescence. At equal intensities of singlet oxygen generation relative intensities of the 1272 and 703 nm bands differed by several orders of magnitude in solutions of different sensitizers. The energy migration from the molecules responsible for the luminescence to bacteriopheophytin and phtalocyanine has been observed. The luminescence is interpreted as dimol emission of solvated singlet molecular oxygen activated by sensitizer molecules.