Quadrupolar magic angle spinning NMR spectra fitted using the Pearson IV function.

The Pearson IV function was used to fit the asymmetric solid-state 27 Al NMR spectra of alumina based catalysts. A high convergence (correlation coefficient is no less than 0.997) between experimental and simulated spectra was achieved. The decomposition of the 27 Al NMR spectra of zinc/aluminum mixed oxides with different Zn/Al molar ratio revealed an increased fraction (6–9%) of pentacoordinated aluminum atoms in these oxides as compared to γ-Al 2 O 3 . As the Zn/Al ratio is raised, the fraction of [AlO 6 ] octahedral units decreases, while the fraction of [AlO 4 ] tetrahedra increases. [ABSTRACT FROM AUTHOR]