Pulsed microwave irradiation effects on the dynamic behavior of a photochemically generated radical pair in a micellar solution

• Published in: Chemical physics letters Vol. 280; no. 5; pp. 481 - 488
• Main Authors: Sakaguchi, Yoshio, Astashkin, Andrei V., Tadjikov, Boris M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 12.12.1997
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/S0009-2614(97)01189-5

The radical pair dynamics in a photochemical hydrogen abstraction reaction of 2-methyl-1,4-naphthoquinone in a sodium dodecylsulfate micelle was modulated by a microwave pulse. After a short resonant 180° microwave pulse, the recombination of the radical pair was enhanced, its rate constant being determined to be (8.3±0.8)×10 6 s −1. Other kinetic parameters were determined by the scanning of the microwave pulse position as follows: the formation of the radical pair (3.3±0.3)×10 7 s −1, the relaxation rate from the triplet (T ±1) levels to the singlet–triplet (T 0) mixed one (3.3±0.3)×10 5 s −1 at 331 mT, and the radical escape rate (5.8±0.6)×10 5 s −1.