Optically Detected Adiabatic Inversion in Phosphorescent Triplet States and the Measurement of Intramolecular Energy Transfer Processes

摘要

The theory and observation of microwave induced population inversion within triplet magnetic sublevels in zero field are presented. It is shown that inversion via adiabatic fast passage can be measured quantitatively by changes in triplet phosphorescence and that population inversion can be accomplished easily and with microwave field strengths even lower than are required for cw saturation. Parameters affecting the ability to invert the sublevel populations, such as dipolar interactions, microwave power, and sweep rates, are studied. General equations relating the intensity of phosphorescence and the fraction of inversion to parameters associated with energy transfer processes into and from the triplet state such as intersystem crossing and radiative and radiationless relaxation are derived and measured for the3pgr; pgr;*state of 2,3hyphen;dichloroquinoxaline.