Two-dimensional single- and multiple-quantum correlation spectroscopy in zero-field nuclear magnetic resonance

We present single- and multiple-quantum correlationJ-spectroscopy detected in zero (< 1 mu G) magnetic field using a Rb-87 vapor-cell magnetometer. At zero field the spectrum of ethanol appears as a mixture of C-13 isotopomers, and correlation spectroscopy is useful in separating the two composite spectra. We also identify and observe the zero-field equivalent of a double-quantum transition in C-13(2)-acetic acid, and show that such transitions are of use in spectral assignment. Two-dimensional spectroscopy further improves the high resolution attained in zero-field NMR since selection rules on the coherence-transfer pathways allow for the separation of otherwise overlapping resonances into distinct cross-peaks. (C) 2020 Elsevier Inc. All rights reserved.