Nuclear magnetic resonance study of 7Li and 133Cs in a nonlinear optical CsLiB6O10 single crystal

The rotation patterns of the nuclear magnetic resonance of 7Li (I=3/2) and 133Cs (I=7/2) in a nonlinear optical CsLiB6O10 single crystal were measured in two mutually perpendicular crystal planes. From these results, the quadrupole coupling constants and the asymmetry parameters were determined at room temperature. For 7Li, e2qQ/h=180±2 kHz and η=0, and for 133Cs, e2qQ/h=574±2 kHz and η=0. The electric field gradient (EFG) tensors of 7Li and 133Cs are axially symmetric: VXX=VYY and VZZ is along the four-fold symmetry around the c-axis. Both the Li ions, which are surrounded by four oxygen atoms, and the Cs ions, which are surrounded by eight oxygen atoms have high symmetry. The principal axes of the EFG tensors of both 7Li and 133Cs are parallel to the crystallographic axis. The temperature dependence of e2qQ/h for 7Li and 133Cs is explained with a single torsional frequency of the Li–O and the Cs–O ions about the Z-axis of the EFG tensor.