Spin Polarization and Spin-Lattice Relaxation in the Lowest Triplet State of Pyrazine at 1.6 Degrees K

摘要

The different mechanisms proposed for the spin-lattice relaxation process of a paramagnetic impurity in ionic crystals are briefly summarized. The decay characteristics of the pyrazine phosphorescence in cyclohexane and benzene matrices at 1.6K and its temperature dependence can best be explained if competition between the spin-lattice relaxation process between the triplet sublevels and the radiative process from one of the sublevels of pyrazine is invoked. A scheme is found to explain the observed temperature effects on the decay characteristics as well as the unique phosphorescence polarization along the N...N axis of the pyrazine molecule. The effect of the magnetic field on the decay curve is demonstrated, and briefly described. (Author)