Spectral Analysis of Quadrupolar NMR Signals by the Padé-Laplace Method

Abstract A new spectral analysis method, referred to as the Pade-Laplace method (PLM), is used for the first time to analyse NMR signals. For this analysis it introduces Laplace transform of the free induction decay (FID) and represents this transform through Pade approximants. When suitably applied this method allows retrieval of the spectral parameters (frequency, amplitude and linewidth) of each NMR line, without any a priori assumption concerning the number of exponential components involved in the FID. Mathematical analysis and numerical tricks of the PLM are discussed in the frame of this important class of signals. Numerical simulations, including two well resolved component FID, free of noise and with various levels of noise, have been performed in order to test the efficiency of the method. Finally, NMR signals from N-methyl imidazole in DMSO have been analysed; agreement with the results of the FT procedure is within experimental accuracy.

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