Quadrupole coupling data have been obtained from analysis of NMR spectra of7Li and27Al in single crystal and polycrystalline ordered LiAl5O8. On axially symmetric sites, values of verbar; ngr;Qverbar; for7Li and27Al are, respectively, 41plusmn;2 kc/sec and 284plusmn;6 kc/sec. On27Al sites with octahedral coordination, verbar; ngr;Qverbar;=683plusmn;25 kc/sec, eegr;=0.347plusmn;0.025, and the orientation of principal axes has been found. An ionic model calculation gives estimates of distortions of the crystal from the ideal spinel form and possible signs for the ngr;Qvalues. A convenient general expression for secondhyphen;order shifts is given, together with results for the positions of the prominent secondhyphen;order features in the line shapes of polycrystalline samples.
展开▼
