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

Area of Science:

• Atomic, Molecular and Chemical Physics
• Spectroscopy
• Quantum Information Science

Background:

• Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful analytical technique.
• Achieving high resolution in NMR can be challenging, especially at zero magnetic field.
• Isotopomers and overlapping resonances often complicate spectral analysis.

Purpose of the Study:

• To present single- and multiple-quantum correlation J-spectroscopy in zero magnetic field.
• To demonstrate the utility of this technique for spectral separation and assignment.
• To enhance spectral resolution and resolve overlapping signals.

Main Methods:

• Utilized a ⁸⁷Rb vapor-cell magnetometer for zero magnetic field detection (<1μG).
• Employed single- and multiple-quantum correlation J-spectroscopy.
• Applied two-dimensional (2D) spectroscopy to analyze coherence-transfer pathways.

Main Results:

• Successfully detected zero-field NMR spectra of ethanol, separating ¹³C isotopomer signals.
• Identified and observed the zero-field double-quantum transition in ¹³C₂-acetic acid.
• Demonstrated improved spectral resolution and separation of overlapping resonances using 2D spectroscopy.

Conclusions:

• Zero-field NMR correlation spectroscopy is effective for separating complex spectra and aiding spectral assignment.
• The observed zero-field double-quantum transitions are valuable for spectral assignment.
• Two-dimensional zero-field NMR significantly enhances resolution, enabling the separation of overlapping resonances.