Deuteron quadrupole resonance studies. Part 9.—1H/2H double resonance in potassium bicarbonate

Abstract

A systematic study of the ²H quadrupole resonance spectra of KHCO₃ by double resonance methods and their changes with deuteration ratio has shown that the two sets of signals observed arise from the bicarbonate ion dimers [HCO₃ . DCO₃]^2– and [DCO₃ . DCO₃]^2–. The ²H quadrupole coupling constants of these two species themselves increase with deuteration ratio, due largely to the lattice expansion. Their intensities can be explained in terms of a relatively simple model for the double resonance process. The anisotropy of the ²H electric field gradient tensor is compared with that of the ¹H chemical shift tensor recently deduced from high-resolution studies of a single crystal, and it is shown that it is reasonable to expect the inequality in the axial components of the two tensors to be related.