Optimized multiple-quantum magic-angle spinning NMR experiments on half-integer quadrupoles

Quadrupolar and Chemical Shift Tensors Characterized by 2D Multiple-Quantum NMR Spectroscopy

“…Upon collecting static 2D NMR correlation spectra with all pulses set to their optimized MQ powder excitation and conversion efficiencies (42), notable deviations from the ideal lineshapes were observed (Fig. 5).…”

Enhanced Sensitivity in RIACT/MQ-MAS NMR Experiments Using Rotor Assisted Population Transfer

“…Subsequent numerical studies (21), however, showed that in the short pulse limit the triple-quantum oscillations in a polycrystalline sample occurred at a faster rate that is proportional to ω 1 and not ω coupling constants of C q = 0.5, 1.5, and 2.5 MHz. In all plots the triple-quantum coherence created from an initial density operator of ρ(0) = I z is shown as a thick gray line, and the triplequantum coherence created from ρ(0) = I In general, the evolution of the triple-quantum coherence generated from ρ(0) = I z more closely follows the ρ(0) = 3I 1−4 z curve, except at very short pulse lengths where it more closely follows the ρ(0) = I 2−3 z curve.…”

Studies on multiple‐quantum magic‐angle‐spinning NMR of half‐integer quadrupolar nuclei under strong rf pulses with a microcoil

“…Amoureux et al experimentally examined the efficiencies of MQ excitation/conversion for various widths and intensities of rf irradiation in the region that the quadrupolar frequency -Q is much larger than the rf intensity -1 (12). This common assumption (-1 ( -Q ) has lead to the generally accepted practical tip of MQMAS that one should use as large rf power as possible so as to attain the optimal MQ excitation/convertion efficiencies.…”