Accessing the long-time limit in diffusion NMR: The case of singlet assisted diffusive diffraction q-space

Area of Science:

• Nuclear Magnetic Resonance (NMR) Spectroscopy
• Materials Science
• Physical Chemistry

Background:

• Standard diffusion measurements are limited by short diffusion times, restricting the study of long-time diffusion dynamics.
• Accessing the long-time limit is crucial for understanding diffusion in complex and macroscopic systems.

Purpose of the Study:

• To extend achievable diffusion times in Nuclear Magnetic Resonance (NMR) studies.
• To enable the investigation of diffusion dynamics in macroscopic cavities (millimeter-sized).
• To access the long-time diffusion limit in diffusive-diffraction studies.

Main Methods:

• Integration of long-lived spin states with pulsed-field gradient (PFG) techniques.
• Utilizing nearly-equivalent spin-1/2 pairs to facilitate extended diffusion time measurements.
• Development and application of a specialized pulse sequence for the long-time diffusion regime.

Main Results:

• Diffusion times of several minutes are now measurable, significantly exceeding current capabilities.
• The method provides access to the long-time diffusion limit in millimeter-sized cavities.
• Numerical simulations and experimental validation confirm the efficacy of the developed pulse sequence.

Conclusions:

• The novel approach successfully extends diffusion time measurements in NMR.
• This technique opens new avenues for studying diffusion in macroscopic systems and at the long-time limit.
• The validated pulse sequence is suitable for future investigations in this extended regime.