Local electronic structure in a LiAl O2 single crystal studied with Li7 NMR spectroscopy and comparison with quantum chemical calculations

The local electronic structure of a γ-LiAl O2 single crystal was investigated with Li7 nuclear magnetic resonance measurements. We observed different sets of spectra which originate from the four crystallographically equivalent but magnetically inequivalent Li sites per unit cell. We find a coupling constant e2 qQ h=115.1±0.6 kHz and an asymmetry parameter η=0.69±0.01. The directions of the principal axes of the electric field gradient tensor at the sites of the Li nuclei have also been determined. We compared these experimental results with quantum chemical calculations at density-functional level and found good agreement.