THE NUCLEAR-MAGNETIC-RESONANCE OF RU-99 AND RN-1O1 IN HEXAGONAL CLOSE-PACKED RUTHENIUM METAL

The nuclear magnetic resonance of Ru-99 and Ru-101 has been observed i n hexagonal close-packed ruthenium metal. As both isotopes possess a n uclear quadrupole moment the field spectra show the characteristics fo r quadrupolar disturbed nuclear magnetic resonance. A computer simulat ion of the experimental spectra yields an electric field gradient of 1 .09 +/- 0.06 x 10(17) V cm(-2) in good agreement with recent band stru cture calculations. The isotropic and axial Knight shifts, K-iso and K -ax deduced from these spectra are 0.49 +/- 0.02% and 0.045 +/- 0.002% , respectively. The rather high positive isotropic Knight shift is mai nly due to the Van Vleck contribution, which is presumably also respon sible for the rather strong anisotropy. The measurement of the spin-la ttice relaxation of the isotopes Ru-99 and Ru-101, carried out at 4.2 K, yields spin-lattice relaxation times (T-1) of 3.7 +/- 0.2 s and 3.1 +/- 0.2 s, respectively.