Electron T/sub 1/ measurements in short-lived free radicals by dynamic polarization recovery

Journal Article · Sun Sep 15 04:00:00 EDT 1985 · J. Chem. Phys.; (United States)

OSTI ID:5370346

Bartels, D M; Lawler, R G; Trifunac, A D

A dynamic polarization recovery method for measurement of electron spin T/sub 1/ relaxation times in free radicals in liquids is described, which is valid even in the presence of chemically induced dynamic electron polarization (CIDEP) and fast chemical decay of the radicals. The method is based on pulsed microwave perturbation and detection of transient magnetization following radical creation in a short pulse. Analysis of the experimental approach and a theoretical description of the method is presented together with a detailed discussion of the advantages and the limitations of the technique. Electron T/sub 1/ measurements are presented for 14 short-lived free radicals generated in aqueous solution. The magnitudes of the observed relaxation times, which range from 0.1 to 4 ..mu..s, are discussed within the framework of current theories of relaxation for small radicals in liquids. It is tentatively concluded that the spin rotation mechanism is responsible for the very short T/sub 1/'s in this series of radicals.

• Research Organization: Chemistry Department, Brown University, Providence, Rhode Island 02912
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5370346
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 83:6; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
AQUEOUS SOLUTIONS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DISPERSIONS
ELECTRON SPIN RESONANCE
FLUIDS
LIQUIDS
MAGNETIC RESONANCE
MIXTURES
RADIATION CHEMISTRY
RADIATION EFFECTS
RADICALS
RADIOLYSIS
REACTION INTERMEDIATES
RESONANCE
SOLUTIONS