Multiple resonances involving electron spin resonance, nuclear magnetic resonance and optical transitions: more than just a game?

Abstract

The detection of hyperfine couplings in large and low-symmetry molecules is often hampered by problems of sensitivity and/or resolution. In such situations solutions to the problem are offered by simultaneously driving n.m.r., e.s.r. and optical transitions leading to well characterized electron–nuclear double and triple resonance (ENDOR, TRIPLE) and optically detected quadrupole resonance (ODNQR) spectra. The basic strategies of these multiple resonance techniques are discussed, together with applications to photosynthetic systems and spin-polarized aromatic molecules.