Enhancing sensitivity or resolution of homonuclear correlation experiment for half-integer quadrupolar nuclei.

Area of Science:

• Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
• Quantum Coherence Phenomena
• Materials Characterization

Background:

• The study builds upon a previously introduced double-quantum homonuclear correlation NMR experiment for half-integer quadrupolar nuclei in solids.
• This technique relies on rotary resonance recoupling for signal generation.

Purpose of the Study:

• To enhance the efficiency of the double-quantum homonuclear correlation NMR experiment.
• To explore the application of additional pulse sequences to improve performance.
• To present an upgraded 2D experiment correlating double- and six-quantum coherences.

Main Methods:

• Application of rotor assisted population transfer (RAPT) and Carr-Purcell-Meiboom-Gill (CPMG) sequences to the existing NMR experiment.
• Development and testing of an upgraded two-dimensional NMR experiment.
• Utilizing sodium-23 (23Na) containing samples (Na2SO4 and Na2HPO4) for validation.

Main Results:

• Substantial efficiency enhancement of the double-quantum NMR experiment was achieved by incorporating RAPT and CPMG sequences.
• An upgraded 2D experiment correlating double- and six-quantum coherences was successfully implemented.
• The upgraded experiment provides high-resolution isotropic spectra but suffers from reduced sensitivity.

Conclusions:

• The integration of RAPT and CPMG sequences significantly boosts the efficiency of solid-state NMR for half-integer quadrupolar nuclei.
• The upgraded 2D experiment offers advanced spectral resolution but is sensitive-dependent.
• The combined approach is feasible for samples where RAPT and CPMG can be effectively applied.