Full-Scale Ab Initio Simulation of Magic-Angle-Spinning Dynamic Nuclear Polarization.

Area of Science:

• Computational chemistry
• Magnetic resonance spectroscopy
• Nuclear magnetic resonance

Background:

• Theoretical models for MAS DNP NMR are crucial for designing polarizing agents but often face accuracy limitations with large spin systems.
• Current models often use phenomenological approaches, balancing quantum mechanical rigor with computational feasibility.

Purpose of the Study:

• To develop a computational method for accurate ab initio MAS DNP NMR simulations of large spin systems.
• To enable in silico design and optimization of DNP polarizing agents and formulations.

Main Methods:

• Employed aggressive state-space restrictions and optimization strategies for large-scale simulations.
• Performed ab initio simulations on spin systems comprising thousands of nuclei.
• Validated simulation results against experimental DNP enhancements and MAS rate dependencies.

Main Results:

• Achieved quantitative reproduction of experimental DNP enhancements, including MAS rate dependence.
• Simulations accurately modeled both frozen solutions and solid materials.
• Identified a novel structural feature in polarizing agents that mitigates spin diffusion barrier effects.

Conclusions:

• The developed computational approach enables accurate, large-scale MAS DNP NMR simulations.
• This facilitates the rational design of advanced DNP polarizing agents.
• Understanding structural features is key to overcoming sensitivity loss in DNP NMR.