Determination of the sign of the deuteron quadrupole coupling constant in the high temperature limit

Abstract

Normally it is impossible to determine the sign of the quadrupole coupling constant in the high temperature limit. However if two nuclei are coupled via the magnetic dipole interaction the characteristic spectra may be modified in such a way that the sign can be determined. This paper discusses the circumstances which are needed to be satisfied by the Hamiltonian describing the form of the interaction between two deuterons and proceeds to describe the features of the deuteron nuclear quadrupole double resonance (NQDR) spectrum which enable the sign to be determined. Comparison with experimental spectra from the crystal hydrates BeSO 4·4H 2O, CH 3COOLi·2H 2O, LiI·3H 2O, LiBr·2H 2O and AlCl 3·6H 2O and the amine groups in adenosine reveals the sign of the quadrupole coupling constant for the first time in the solid state. It is found that the quadrupole coupling constant may be positive or negative depending on the environment of the deuteron sites.