Li-7 and Rb-87 nuclear magnetic resonance in a LiRbSO4 single crystal withthe growth twin domain

The Li-7 and Rb-87 NMR in a LiRbSO4 single crystal with the growth twin dom ain grown by the slow evaporation method were investigated by employing a B ruker FT NMR spectrometer. Instead of the simple one set of signals caused by quadrupole interaction, three sets of NMR signals were obtained. From th ese results, all parameters were determined, and all lead to the same value s for the quadrupole coupling constant and asymmetry parameter. The Li-7 NM R parameter in the LiRbSO4 crystal was axially symmetric, whereas the Rb-87 NMR parameter was non-axially symmetric; the lithium ion is surrounded by oxygen atoms located on a regular tetrahedron, and the resultant coordinati ng rubidium ion is surrounded by slightly distorted oxygen atoms located at nine regular tetrahedra. The obtained results can be explained by the exis tence of three kinds of growth twin domain, rotated with respect to each ot her by 120 degrees around the c-axis.