Magnetic Isotope Effect in Radical Reactions

1 Introduction.- 1.1 Origin of magnetic isotope effect in radical reactions.- 1.2 Favourable conditions for magnetic isotope effect.- 1.3 Some specific features of magnetic isotope effect.- 1.4 What can be gained from magnetic isotope effect?.- 1.5 Basic steps in studying magnetic isotope effect.- 2 Main concepts of the theory of magnetic isotope effect.- 2.1 Macroscopic and microscopic parameters.- 2.2 Radical pairs.- 2.3 Multiplicity and reactivity of radical pairs.- 2.4 The hyperfine coupling.- 2.5 Singlet-triplet transitions in radical pairs induced by the hyperfine interaction.- 2.6 Manifestations of radical pair spin conservation rules in singlet-triplet mixing induced by the isotropic hyperfine coupling.- 2.7 Kinetic equations for radical pair recombination.- 3 Theoretical description of magnetic isotope effect in the Earth’s magnetic field.- 3.1 Radical pairs with one magnetic nucleus (isotropic hyperfine coupling).- 3.2 Radical pairs with magnetically equivalent nuclei (isotropic hyperfine coupling).- 3.3 Radical pairs with many magnetically non-equivalent nuclei (isotropic hyperfine coupling).- 3.4 Magnetic isotope effect induced by the anisotropic hyperfine interaction (paramagnetic relaxation).- 3.5 Magnetic isotope effect in reaction kinetics.- 4 Magnetic isotope effect in the presence of external magnetic fields.- 4.1 Magnetic isotope effect as affected by constant fields.- 4.1.1 Anisotropic hyperfine interaction (the so-called relaxation mechanism of singlet-triplet transitions).- 4.1.2 Isotropic hyperfine interaction.- 4.2 Resonant microwave field pumping.- 5 Experimental evidences of magnetic isotope effect.- 5.1 Enrichment of 13C in dibenzyl ketone during photolysis.- 5.1.1 Photolysis of dibenzyl ketone in homogeneous solutions.- 5.1.2 Photolysis of dibenzyl ketone in micelles.- 5.1.3 Magnetic isotope effect in photoinduced emulsion polymerization.- 5.2 Magnetic isotope effect in radiolysis of aromatic hydrocarbon solutions in alkanes.- 5.3 Magnetic isotope effect for heavy elements.- 5.4 Magnetic isotope effect for biradical reaction pathways.- 5.5 Magnetic isotope effect in reaction rates.- 5.6 Isotope enrichment by resonant microwave pumping.- 6 Some perspectives.- References.