Applied Magnetic Resonance

, Volume 18, Issue 3, pp 343–350 | Cite as

Effect of charge transfer state on the exchange interaction of radical-triplet encounter pairs

  • A. Kawai
  • K. Shibuya
  • K. Obi


Chemically induced dynamic electron polarization (CIDEP) of galvinoxyl was measured in various excited molecule-galvinoxyl systems prepared by laser photolysis. Most of the systems examined showed net emission CIDEP, which is well explained by the quartet precursor radical-triplet pair mechanism with exchange interaction,J, of negative sign (quartet is higher than doublet). Several systems with molecules such as naphthalene, quinoxaline, biphenyl and triphenylene, however, showed net absorption CIDEP. Time profiles of CIDEP and kinetic analysis of quenching suggest that net absorption CIDEP is generated during the triplet quenching process by the galvinoxyl radical. We conclude that the net absorption CIDEP is produced during the triplet quenching if theJ value of radical-triplet encounter pair is positive. This is the first report of the radical-triplet encounter pairs with positiveJ value. The mechanism for this unusual positive sign ofJ value is discussed on the basis of the spin-selective configuration interaction between the doublet spin correlated states of radical-triplet and charge transfer encounter pairs.


Quinoxaline Excited Molecule Charge Transfer State Laser Photolysis Triplet Molecule 


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Copyright information

© Springer 2000

Authors and Affiliations

  • A. Kawai
    • 1
  • K. Shibuya
    • 1
  • K. Obi
    • 2
  1. 1.Department of Chemistry, Graduate School of Science and EngineeringTokyo Institute of TechnologyTokyoJapan
  2. 2.Department of Chemical and Biological ScienceJapan Women’s UniversityTokyoJapan

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