Trimers atomic fluorescence

In the course of similar experiments in which the liquid nitrogen baffle above is removed, an intriguing phenomena has been observed. We have been able to induce sodium D-line fluorescence upon single photon pumping at energies far lower than that required to simultaneously dissociate dimeric sodium and produce emission from excited atoms. The atomic fluorescence and its characterization will be the subject of our following discussion. Briefly, we have observed and characterized laser induced atomic fluorescence upon photodissocia-tlon of sodium trimers formed under a variety of conditions. 

Laser Induced Atomic Fluorescence and Sodium Trimer Fluctuation Bands... 

Photophysical properties of Th(TPP)(acac)2 have also been examined and compared with those of the trimeric species [Th(TPP)(OH)2]3 (Tran-Thi et al. 1992). The fluorescence of the porphyrin (3t,jt ) state is severely quenched in both compounds (triplet state (Tp 208 ps). The triplet yield of the trimer (0.38), however, is drastically reduced with respect to that of the monomer (1.00) even though the former contains three thorium atoms. This has been attributed to the enhancement of the probability of deactivation of the singlet excited states via an internal conversion pathway. 

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