Interatomic distance measurement in solid-state NMR between a spin- 1/2 and a spin- 5/2 using a universal REAPDOR...

Area of Science:

• Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
• Quantum Spin Physics
• Materials Science

Background:

• Accurate interatomic distance measurements are crucial in solid-state NMR.
• Previous methods often require complex calculations or are limited in scope.
• The rotational echo double resonance (REAPDOR) experiment offers a pathway for distance determination.

Purpose of the Study:

• To propose a universal curve for solid-state NMR REAPDOR experiments.
• To provide a simplified method for measuring interatomic distances in spin-1/2-spin-5/2 systems.
• To validate the universal curve by fitting experimental data without complex density matrix calculations.

Main Methods:

• Acquisition of REAPDOR data at varying rotor spinning frequencies.
• Simultaneous fitting of all data points to a proposed universal formula.
• Application of the method to a tyrosine sample with a 13C-17O label.

Main Results:

• A universal curve applicable to isolated spin-1/2-spin-5/2 pairs was successfully proposed.
• Experimental REAPDOR data from three separate experiments were fitted simultaneously to the universal formula.
• The 13C-17O interatomic distance in tyrosine was measured as 2.45 Å.
• The determined dipolar coupling (Dfit = 278 Hz) showed an 8% error, well within the 15% tolerance.

Conclusions:

• The proposed universal curve offers a straightforward approach for interatomic distance determination using solid-state NMR REAPDOR.
• The method eliminates the need for full density matrix calculations, simplifying experimental analysis.
• The accurate measurement of the 13C-17O distance in tyrosine validates the efficacy and precision of this novel approach.