Magnetic resonance optically detected

Optically detected magnetic resonance (ODMR) has yielded valuable information about dynamics of long-lived photoexcitations of conjugated polymers. The technique relies upon the paramagnetic interaction of excitations with an applied magnetic field. For a particle with non-zero spin, placed in a magnetic field, the Hamiltonian is  

For electron spin resonance (ESR) measurements, the sample is placed in a resonant microwave cavity between the pole pieces of an electromagnet. The magnetic field is gradually increased, which induces a Zeeman splitting of the excita- 

Magnetic resonance also has an effect on photoexcitation dynamics as the absorption of microwaves will equalize the populations of the two coupled spin sublevels. Consider two triplet sublevels X and Y with sublevel populations generation rates and recombination rates 7 ,= l/r,. Under steady state con- 

Eor spin-1/2 excitations such as electrons and holes in normal semiconductors or polarons in conjugated polymers, a single resonance is found centered at the field 

The zero field splitting (ZFS) parameters D and E of the triplet exciton are  

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Glasbeek M (2001) Excited State Spectroscopy and Excited State Dynamics of Rh(III) and Pd(II) Chelates as Studied by Optically Detected Magnetic Resonance Techniques. 213 95-142 Glass RS (1999) Sulfur Radical Cations. 205 1-87 Gobbi L, see Diederich F (1999) 201 43-129... 

A number of other laser spectroscopic techniques are of interest but space does not permit their discussion. A few specialized methods of detecting laser absorption worthy of mention include multiphoton ionization/mass spectrometry (28), which is extremely sensitive as well as mass selective for gas-phase systems optically detected magnetic resonance (29) laser intracavity absorption, which can be extremely sensitive and is applicable to gases or solutions (30) thermal blooming, which is also applicable to very weak absorbances in gases or liquids (31) and... 

K. Morigaki, Optically Detected Magnetic Resonance J. Dresner, Carrier Mobility in a-Si H... 

Optically detected magnetic resonance (ODMR) studies of -iT-conjugated polymer-based hght emitting diodes (LEDs) J. Shinar Organic Electroluminescent Materials and Devices, S. Miyata and H.S. Nalwa, Eds., Gordon and Breach, Amsterdam, pp.177-202... 

L.S. Swanson, J. Shinar, Y.W. Ding, and T.J. Barton, Photoluminescence, electroluminescence, and optically detected magnetic resonance study of 2,5-dialkoxy derivatives of poly(p-phenylene acetylene) (PPA) and PPA-based light-emitting diodes, Synth. Met., 55 1-6, 1993. 

D was determined by measuring the Ams = 2 EPR transition, where ms is the spin quantum number. Several years later, D and E were obtained directly by observation of the Ams = 1 EPR signals/33 1 In 1973, Zuclich et alP redetermined the triplet-state splitting parameters of tyrosine using optically detected magnetic resonance (ODMR) spectroscopy. 

J. Zuclich, D. Schweitzer, and A. H. Maki, Optically detected magnetic resonance of the tryptophan phosphorescent state in proteins, Photochem. Photobiol. 18, 161-168 (1973). 

K. Ugurbil, A. H. Maki, and R. Bersohn, Study of the triplet state properties of tyrosines and tryptophan in azurins using optically detected magnetic resonance, Biochemistry 16, 901-907 (1977). 

K. L. Bell and H. C. Brenner, Phosphorescence and optically detected magnetic resonance study of the tryptophan residue in human serum albumin, Biochemistry 21, 799-804 (1982). 

W. C. Galley, Heterogeneity in protein emission spectra, in Concepts of Biochemical Fluorescence Vol. 2 (R. F. Chen and H. Edelhoch, eds.), pp. 409-439, Marcel Dekker, New York (1976).32. S.-Y. Mao and A. H. Maki, Comparative phosphorescence and optically detected magnetic resonance studies of fatty acid binding to serum albumin, Biochemistry 26, 3576-3582 (1987). 

M. V. Hershberger, A. H. Maki, and W. C. Galley, Phosphorescence and optically detected magnetic resonance studies of a class of anomalous tryptophan residues in globular proteins, Biochemistry 19, 2204—2209 (1980). 

Langof, L. Ehrenfreund, E. Lifshitz, E. Continuous-Wave and Time-Resolved Optically Detected Magnetic Resonance Studies of Nonetched/Etched InP Nanocrystals. J. Phys. Chem. B 2002, 106, 1606-1612. 

The dimer (OEP)Sc—O—Sc(OEP) has been examined by optically detected magnetic resonance with the conclusion that the rings are approximately coplanar.27 The NMR spectra of the dimer and the monomer show that the methylene protons are anisochronous, this probably not being caused by hindered rotation but by the inherent asymmetry of the ligands.28... 

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