Theory of the Nuclear Resonance Spectrum of a Polar Liquid in an Alternating Electric Field

It is suggested that the small secular effects produced in the NMR spectrum of a polar liquid as a result of molecular alignment in an electric field may be detected most easily through the sidebands produced when the field has an ac component. A general modulation theory previously developed is applied to predict the locations and intensities of these sidebands as functions of the relevant molecular and experimental parameters for three forms of the alignment-modulated spin Hamiltonian: (1) anisotropic chemical shift, (2) quadrupole interaction, (3) anisotropic shift plus direct and indirect dipole—dipole coupling.