Radiation chemistry under magnetic fields. Spin coherence effects

Abstract

Publisher Summary This chapter discusses the spin coherence effect in relation to radiation chemistry under magnetic fields. An in-depth study of spin coherence effects provides information related to the information available from magnetic resonance studies. The frequencies of quantum beats and the positions of lines in magnetically affected reaction yield curve (MARY)-spectra are determined by the same parameters as the electron spin resonance (ESR) spectrum structure. The methods discussed in the chapter can be considered as the variants of ESR-spectroscopy of spincorrelated radical ion pairs without mw-pumping. The main advantage of these methods as well as the optically detected (OD) ESR technique is their extremely high sensitivity. Recording luminescence, it is possible to study the spin-correlated pairs at stationary concentrations down to 100 particles per sample. Therefore, the weak radioactive sources can be used for radical ion pairs generation. Compared with the OD ESR technique, spin coherence effect, however, has an essential advantage. The spin coherence effect can be used to study the spin-correlated pairs with shorter lifetimes. In OD ESR, this time is limited by the time of electron spin flip around microwave magnetic field of spectrometer, whereas in the case of quantum beats or MARY spectroscopy, this limit depends on hyperfine fields or the difference in radical g-factors.