Magnetic field effects on yields and decays of fluorescence of pyrimidine vapor: Excited rovibronic level dependence

Publisher Website
Google Scholar
Abstract
External magnetic field effects on yields and decays of fluorescence of pyrimidine vapor on excitation into various rotational levels belonging to the vibrationless level or the 6a1 level of S1 have been studied in a supersonic jet or in a bulk gas at room temperature with a field strength of 0–150 G. The fast component of fluorescence is not affected by an external magnetic field, whereas the slow fluorescence is quenched by a field except for excitation at the R(0) line belonging to the 0–0 transition. The fluorescence quenching is more effective at the 6a1 level than that at 00, indicating that the level density of the triplet state coupled to the singlet state plays an important role in the magnetic mixing of the triplet spin sublevels, in terms of which the fluorescence quenching by a magnetic field is interpreted. The excited rotational level dependence of the fluorescence quenching by a magnetic field is attributed to K scrambling in the triplet manifold following intersystem crossing.