The combination of X-ray diffraction and nuclear quadrupole resonance studies of crystals

Abstract

The application of single-crystal Zeeman nuclear quadrupole resonance (NQR) in combination with diffraction studies is discussed. Bond directions and bond angles are found by the Zeeman spectroscopy of NQR, as are symmetry elements of the structures. Centrosymmetry may be differentiated from polar structures. Weak deformations of the valence electron shell by mutual polarization can be recognized and the double-bond character of a bond may be estimated. The method is quite valuable in the study of hydrogen bonds and of dynamics of molecules such as D 2 O and the groups ―CD 3 and ND 3 . Most useful is the method of the combination of X- and N-diffraction because of its sensitivity to the charge distribution around atoms and its location of time scale in dynamical effects.