Radiofrequency magnetic field effects on chemical reaction yields

The influence of radiofrequency magnetic fields (1-80 MHz) on the yields of radical recombination reactions is investigated. A decrease in the recombi nation probability of radical ion pairs (monitored via exciplex fluorescenc e) is detected when the radiofrequency matches energy-level splittings aris ing from hyperfine interactions in the radicals. The dependence of the osci llating magnetic field effect (OMFE) spectrum on radiofrequency field stren gth and hyperfine coupling constants is presented for several reaction part ners. The experimental studies are supported by theoretical simulations of recombination yields based on the radical pair mechanism (RPM). (C) 2000 El sevier Science B.V. All rights reserved.