Long-term stability of rotor-controlled MAS frequencies to 0.1 Hz proved by 14N MAS NMR experiments and simulations.
Experimental and simulated 14N MAS NMR spectra of the NH4+ ions in the two polymorphs, mS60 and mP60, of (NH4)2MoO4 are used to illustrate that a long-term stability of rotor-controlled MAS frequencies to 0.1 Hz can be achieved using commercial instrumentation (MAS speed controller and 7.5 mm MAS probe with a single marked rotor) attached to a highly pressure-stabilized air supply. A new modification of the STARS simulation software employs a Gaussian distribution for the experimental spinning frequency around the frequency set for the MAS speed controller. A simulated spectrum is then obtained by summation of several calculated spectra for evenly spaced spinning frequencies around the set frequency with relative weight factors corresponding to the Gaussian distribution.
Jakobsen
Hans J
HJ
Instrument Centre for Solid-State NMR Spectroscopy, Department of Chemistry, University of Aarhus, DK-8000 Aarhus C, Denmark. hja@chem.au.dk
Hove
Anders R
AR
Bildsøe
Henrik
H
Skibsted
Jørgen
J
Brorson
Michael
M
D000465:Algorithms; D003198:Computer Simulation; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D009584:Nitrogen / Q000737:chemistry*; D011846:Radio Waves; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity
D009584:Nitrogen