ββ-detected NMR of 8Li in the normal state of 2H-NbSe2NbSe2

ββ-NMR of isolated 8Li has been investigated in the normal state of 2H-NbSe2NbSe2. In a high magnetic field of 3 T a single resonance is observed with a Gaussian line width of 3.5 kHz. The line shape varies weakly as function of magnetic field and temperature but has a strong orientation dependence. The nuclear electric quadrupole splitting is unresolved implying that the electric field gradients are 10–100 times smaller than in other non-cubic crystals. The nuclear spin relaxation rate is also anomalously small but varies linearly with temperature as expected for Korringa relaxation in a metal. These results suggest that Li adopts an interstitial position between the weakly coupled NbSe2NbSe2 layers and away from the conduction band.