Wide-Line ¹⁴N NMR in Solids and Reorientation-Induced Redistribution of Isochromats

Direct detection of nitrogen-14 in solid-state NMR spectroscopy

“…15), acquiring the spectrum from potassium nitrate (C Q = 751 kHz, η Q = 0.022) at 7.05 T [78]. The total width of this 14 N pattern is ca.…”

“…Redistribution of Isochromats) [78]. This technique takes advantage of the fact that only a very small section of the powder pattern is observed at any one time.…”

“…RotIsseRIe, Hill and Yesinowski were able to record a sub-spectrum from potassium nitrate using a recycle delay of just 2 s, despite a 14 N spin-lattice relaxation time of T 1 = 40 s [78], and this approach was subsequently used to record one half of the 14 N spectrum from silicon nitride (C Q ≈ 2.1 MHz) [2].…”

NMR Imaging Using Second Order Quadrupole Broadened Resonances

“…Because of the low signal-to-noise ratio, 64,000 acquisitions were averaged for each echo. Though not pursued here, the use of slow sample rotation during the measurement could be used to decrease the total acquisition time (20,21). The echo signals as a function of gradient strength were stored and the image was reconstructed from the resulting pseudo FID using a fast Fourier transform.…”

Comparison of various NMR methods for the indirect detection of nitrogen-14 nuclei via protons in solids

“…The combination of these three unfavorable properties leads to a very weak and broad 14 N SQ NMR signal. Generally, the direct detection of one-dimensional (1D) 14 N SQ signal of solids is a challenging task, which has notably been achieved in static samples using piecewise acquisition, 4 or frequency-swept excitation. 5 It must be mentioned that 14 N nuclei have also been directly detected under MAS, which improves the resolution.…”