Numerical recipes for faster MAS-DNP simulations

Numerical simulations of Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP) have trans -formed the way the DNP process is understood in rotating samples. In 2012, two methods were concomi-tantly developed to simulate small spin systems (< 4 spin-1/2). The development of new polarizing agents, including those containing metal centers with S > 1/2, makes it necessary to further expand the numerical tools with minimal approximations that will help rationalize the experimental observa-tions and build approximate models. In this paper, three strategies developed in the past five years are presented: an adaptive integration scheme, a hybrid Hilbert/Liouville formalism, and a method to trun-cate the Liouville space basis for periodic Hamiltonian. Each of these methods enable time savings rang -ing from a factor of 3 to > 100. We illustrate the code performance by reporting for the first time the MAS-DNP field profiles for AMUPol, in which the couplings to the nitrogen nuclei are explicitly considered, as well as Cross-Effect MAS-DNP field profiles with two electrons spin 5/2 interacting with a nuclear spin 1/2. (c) 2021 Elsevier Inc. All rights reserved.

Automated summary

Numerical simulations have transformed the understanding of the DNP process in rotating samples, with the development of new polarizing agents requiring expansion of numerical tools to rationalize experimental observations and build models.