Connection of the pulse experiment parameters with the shape of the heteronuclear NMR J-spectrum
The impact of the type of the pulse sequence, the registration algorithm and the data processing regime on the shape of the two-dimensional heteronuclear J-spectrum are studied. It is shown that the widely used processing techniques for two-dimensional heteronuclear J-spectra can lead to distortion of lineshapes and a significant loss of information. We suggest a scheme of optimal transformation of the free induction decay signal which allows to obtain a phase-sensitive spectrum with cross-peaks having absorption lineshapes in both frequency coordinates. The result was tested experimentally on chloroform-^13C, a model spin system of the AX type.