Field-stepwise-swept QCPMG solid-state In NMR of indium oxide.

Experimental and theoretical investigations of indium-115 electric-field-gradient (EFG) tensors of indium(III) oxide, InO, have been presented. Field-stepwise-swept QCPMG solid-state In NMR experiments are carried out at T ​= ​120 ​K, observed at 52.695 ​MHz, and in the range of external magnetic fields between 4.0 and 6.5 ​T. The spectral simulations yield the quadrupolar coupling constant, C value, of 183(2) MHz and the asymmetry parameter, η, of 0.05(5), for In(1), and that of 126(2) MHz and η of 0.86(5) for In(2). Quantum chemical calculations are carried out to provide In EFG tensor orientations with respect to the molecular structure. A relationship between operative frequencies and variable ranges of external magnetic fields is briefly discussed for field-swept solid-state In NMR.