Wavelength dependence of the efficiency of singlet oxygen generation upon photoexcitation of photosensitizers

The dependence of the efficiency of singlet oxygen ( 1 Δ g ) generation upon excitation of photosensitizer at different wavelength was observed for several derivatives of palladium porphyrin in carbon tetrachloride. The efficiency of singlet oxygen generation upon excitation in a blue region of the spectrum (Soret band) exceeds by several times the efficiency at excitation in the red spectral region (Q band). The effect of enhancement of singlet oxygen generation upon CW photoexcitation to Soret band of photosensitizer may be explained by influence of high laying triplet states of a donor molecule on the triplet-triplet energy transfer.