title: Macroscopic nuclear spin diffusion constants of rotating polycrystalline solids from first-principles simulation.
abstract: A method for quantitatively calculating nuclear spin diffusion constants directly from crystal structures is introduced. This approach uses the first-principles low-order correlations in Liouville space (LCL) method to simulate spin diffusion in a box, starting from atomic geometry and including both magic-angle spinning (MAS) and powder averaging. The LCL simulations are fit to the 3D diffusion equation to extract quantitative nuclear spin diffusion constants. We demonstrate this method for the case of (1)H spin diffusion in ice and L-histidine, obtaining diffusion constants that are consistent with literature values for (1)H spin diffusion in polymers and that follow the expected trends with respect to magic-angle spinning rate and the density of nuclear spins. In addition, we show that this method can be used to model (13)C spin diffusion in diamond and therefore has the potential to provide insight into applications such as the transport of polarization in non-protonated systems.
authors.affiliation: Université de Lyon, Institut de Sciences Analytiques (CNRS/ENS Lyon/UCB Lyon1), Centre de RMN à très hauts champs, 5 rue de la Doua, 69100 Villeurbanne, France.
authors.forename: Meghan E
authors.initials: ME
authors.lastname: Halse
authors.affiliation: Université de Lyon, Institut de Sciences Analytiques (CNRS/ENS Lyon/UCB Lyon1), Centre de RMN à très hauts champs, 5 rue de la Doua, 69100 Villeurbanne, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Zagdoun
authors.affiliation: Université de Lyon, Institut de Sciences Analytiques (CNRS/ENS Lyon/UCB Lyon1), Centre de RMN à très hauts champs, 5 rue de la Doua, 69100 Villeurbanne, France.
authors.forename: Jean-Nicolas
authors.initials: JN
authors.lastname: Dumez
authors.affiliation: Université de Lyon, Institut de Sciences Analytiques (CNRS/ENS Lyon/UCB Lyon1), Centre de RMN à très hauts champs, 5 rue de la Doua, 69100 Villeurbanne, France; Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland. Electronic address: lyndon.emsley@epfl.ch.
authors.forename: Lyndon
authors.initials: L
authors.lastname: Emsley
keywords: Low-order correlations in Liouville space (LCL); Numerical simulation; Polarization transport; Solid-state NMR