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Updated: Aug 8, 2025
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A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
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Windowed cross polarization at 55 kHz magic-angle spinning
Evgeny Nimerovsky1, Stefan Becker1, Loren B Andreas1
1Department of NMR based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen, Germany.
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|February 27, 2023
Summary
Windowed cross polarization (wCP) in solid-state NMR follows new matching conditions. These conditions, similar to standard cross polarization (CP), depend on pulse flip angle rather than radiofrequency field strength.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
- Quantum Control in Magnetic Resonance
Background:
- Cross polarization (CP) via Hartmann-Hahn matching is fundamental to solid-state MAS NMR.
- Windowed cross polarization (wCP) introduces unique matching conditions.
- Understanding these conditions is crucial for optimizing NMR experiments.
Purpose of the Study:
- To investigate the matching conditions of windowed cross polarization (wCP) at high magic-angle spinning frequencies.
- To compare wCP transfer conditions with standard CP conditions.
- To develop an analytical approximation for wCP matching.
Main Methods:
- Experimental investigation of wCP at 55 kHz MAS.
- Application of fictitious spin-1/2 formalism.
- Utilizing average Hamiltonian theory.
- Data acquisition at high magnetic fields (up to 1200 MHz).
Main Results:
- Observed similarity between wCP and CP transfer conditions when considering pulse flip angle.
- Derived an analytical approximation matching the observed transfer conditions.
- Demonstrated that wCP transfers and selectivity relate to flip angle (average nutation).
Conclusions:
- wCP matching conditions are analogous to CP, governed by flip angle rather than RF field strength.
- The derived analytical approximation accurately describes wCP behavior.
- Flip angle is a key parameter for controlling wCP efficiency and selectivity in solid-state NMR.
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