The Determination of the Structure of Low Temperature Triplet Energy Traps Using PMDR Methods. I. The Magnetic Axes of Hexachlorobenzene Excimers.

摘要

Using linearly polarized microwave radiation,the optically detected microwave signal of the zerofield transitions of the hexachlorobenzene broad excimer type emission is studied as a function of the angle between the microwave H vector field and the crystal axes. The dependence of the PMDR signal on the angle between the H vector field of the linearly polarized microwave and crystal axes is examined. From these studies,the exact orientation of the three orthogonal magnetic axes of a phosphorescent triplet state in a single crystal host can be elucidated if three microwave polarization ratios are determined. The method is applied to determine the principal magnetic axes of the triplet state giving rise to the excimer type emission of the hexachlorobenzene crystal at 1.6K. (Author)