Microwave-induced triplet-triplet absorption in organic molecules

The effect of a saturating microwave field in resonance with the zero‐field levels of an organic triplet state on the triplet‐triplet absorption is examined. The change in triplet‐triplet absorption intensity is shown to be due to microwave alteration of the over‐all steady state population in the lowest triplet state. The microwave‐induced intensity changes for triplet‐triplet absorption can be calculated in terms of the dynamical rate constants for the individual spin levels of the triplet state. Results of these calculations are compared with experimentally observed triplet‐triplet absorption intensity changes for several nitrogen heterocyclic compounds.

[1]  J. Schmidt,et al.  Optical pumping in an organic crystal: quinoxaline in durene , 2002 .

[2]  C. Harris,et al.  On the Lowest Triplet State of Substituted Benzenes. III. Optically Detected Magnetic Resonance Studies on the 3π π State of 1,2,4,5‐Tetrabromobenzene and 1,2,4,5‐Tetrachlorobenzene , 1972 .

[3]  J. Hayes,et al.  Triplet Absorption Detection of Magnetic Resonance in a Photoexcited Triplet State , 1972 .

[4]  N. Hirota,et al.  Steady State and Transient Phosphorescence Microwave Double Resonance (PMDR) Studies of Aromatic Carbonyl Molecules; Studies of Experimental Conditions and Properties of π‐π* Triplet States , 1972 .

[5]  M. El-Sayed.  Optical Pumping of the Lowest Triplet State and Multiple Resonance Optical Techniques in Zero Field , 1971 .

[6]  W. S. Veeman,et al.  Microwave induced delayed phosphorescence , 1969 .

[7]  Jan F. Schmidt,et al.  Optical detection of zero-field transitions in phosphorescent triplet states , 1968 .

[8]  A. Zahlan.  The Triplet State , 1967 .

[9]  Mostafa A. El-Sayed,et al.  Spin—Orbit Coupling and the Radiationless Processes in Nitrogen Heterocyclics , 1963 .

[10]  Jan F. Schmidt,et al.  The dynamics of populating and depopulating the phosphorescent triplet state as studied by microwave induced delayed phosphorescence , 1971 .

[11]  M. El-Sayed,et al.  Optical detection of electron-electron double resonance (EEDOR) in zero field of the triplet state , 1970 .

[12]  J. H. Waals,et al.  Phosphorescence and spin polarization. A preliminary report , 1967 .