MAS NMR spectra of quadrupolar nuclei in disordered solids: The Czjzek model

27Al NMR Studies of Aluminosilicate Glasses

“…One option involves generating normal distributions of two EFG tensor components of {V xx ,V yy ,V zz }, whereas the third one is deduced by the restriction V xx +V yy +V zz ¼ 0 of the traceless property of the tensor, from which either each distribution of C Q and η is generated [105], or η is (arbitrarily) assumed to be fixed [26,106]. Simpler approaches (albeit not physically sound, as discussed by de Lacaillerie [107]), assume a Gaussian distribution of C Q , while the asymmetry parameter is either kept constant [108][109][110][111] or distributed independently [112]. The currently most popular distribution is that of Czjzek et al [113], first implemented for analyzing M€ ossbauer spectra and later introduced to NMR on quadrupolar nuclei by Massiot and coworkers [114,115].…”

Tannin Fingerprinting in Vegetable Tanned Leather by Solid State NMR Spectroscopy and Comparison with Leathers Tanned by Other Processes

“…The quadrupolar nature of the 27 Al nucleus with a nuclear spin I = 5/2 means that the 27 Al resonance lineshape is responsive to electric field gradients at the nucleus, which are a function of its bonded and non-bonded environment, particularly the nature and symmetry of the inner and outer coordination spheres. The lineshape is potentially amenable to modelling in terms of Al (III) coordination environment and the distribution of these environments [42] but we have not attempted this.…”

The MAS NMR study of solid solutions based on the YAG crystal

“…The second integration is the weighted average of the powder lineshapes over all possible quadrupolar parameters  Q and . The distribution of quadrupolar parameters is described by the function p( Q ,) and various approaches to choice of this function have been discussed in [19,20]. In this work, we used the Dmfi t model of MAS NMR spectrum and the Lorentzian or Gaussian curves with the broadening parameters  L or  G , which indicate a distribution of slightly distinct environment of nuclei [19].…”

“…The Dmfi t program [19,20] was used to simulate the 27 Al MAS NMR spectra and to extract the isotropic chemical shifts ( iso ), quadrupolar coupling constants (C Q ), and the asymmetry parameters (). are observed in YAG, contain two peaks corresponding to the tetragonal (AlO 4 ) and octahedral (AlO 6 ) structural atomic groups [10].…”