NMR study of CuAl2: 27Al, 63Cu, and 65Cu quadrupole and anisotropic shift interactions

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Abstract
The nuclear magnetic resonance spectra of 27Al, 63Cu, and 65Cu have been studied in a polycrystalline specimen of the intermetallic compound CuAl2 of the C16 structure type at room temperature between 3 and 40 MHz. The 27Al spectra yield to interpretation in terms of a completely anisotropic Knight shift and an asymmetric nuclear electric quadrupole interaction. The observed field separations of the several 27Al quadrupole satellite spectral features at fixed frequencies yield values of the lowest quadrupole frequency νQ = 420.2(8) kHz and asymmetry parameter η = 0.413(9). The 27Al satellite features also yield the three Knight shift parameters Kx = 0.159(1) %, Ky = 0.153(2) %, and Kz = 0.148(10) %. Excellent agreement has also been obtained between observed 27Al central line shape and the theoretical shapes of J. F. Baugher, H. M. Kriz, P. C. Taylor, and P. J. Bray, J. Magn. Reson. 3, 415 (l970). The 63Cu and 65Cu central lines exhibit a strong second and a fourth order quadrupole splitting with νQ(63Cu) = 7.54(17) MHz and νQ(65Cu) = 7.05(18) MHz. An analysis of the copper Knight shift is also presented.