High resolution, high sensitivity proton NMR spectra of solids obtained using continuous wavelet transform analysis

The application of continuous wavelet transform (CWT) analysis to the free-induction decay (FID) signals of SPEDA (single pulse excitation with delayed acquisition) solid state NMR spectroscopy is demonstrated to yield high sensitivity, high resolution, phase corrected and quantitative proton spectra, without using homonuclear decoupling or high speed sample rotation. Moreover, a better description of the spin dynamics (the time evolution of the resonance frequencies) can be obtained from the CWT spectrogram. Three typical polycrystalline compounds are used to verify the versatility of this technique which generates spectra with the same, or higher, quality on comparison with those obtained using the CRAMPS (combined rotation and multiple pulse spectroscopic) technique.