Chirality-Sensitive Effects Induced by Antisymmetric Spin-Spin Coupling

The chapter introduces the concepts of direct and indirect spin–spin coupling as well as hyperfine spin–spin coupling. It is shown that a chiral molecule with a spin pair coupled by an antisymmetric interaction carries an induced electric dipole moment whose direction depends on the handedness of the molecule. Finding this induced dipole, in turn, serves as the starting point for the derivation of the nuclear magnetoelectric resonance Hamiltonian and analysis of spin dynamics under the influence of an externally applied electric field. Four effects that enable direct chirality sensing in nuclear magnetic resonance spectroscopy are also described with emphasis on the relationships between chirality, antisymmetry of spin–spin coupling, electric dipole moment, and molecular structure. Several capacitive devices capable of generating an electric field with properties suitable for nuclear magnetoelectric resonance experiments, in which the central role is played by spin–spin couplings, are described.