title: Dissipative particle dynamics of diffusion-NMR requires high Schmidt-numbers.
abstract: We present an efficient mesoscale model to simulate the diffusion measurement with nuclear magnetic resonance (NMR). On the level of mesoscopic thermal motion of fluid particles, we couple the Bloch equations with dissipative particle dynamics (DPD). Thereby we establish a physically consistent scaling relation between the diffusion constant measured for DPD-particles and the diffusion constant of a real fluid. The latter is based on a splitting into a centre-of-mass contribution represented by DPD, and an internal contribution which is not resolved in the DPD-level of description. As a consequence, simulating the centre-of-mass contribution with DPD requires high Schmidt numbers. After a verification for fundamental pulse sequences, we apply the NMR-DPD method to NMR diffusion measurements of anisotropic fluids, and of fluids restricted by walls of microfluidic channels. For the latter, the free diffusion and the localisation regime are considered.
authors.affiliation: Laboratory for Simulation, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany.
authors.forename: Mueed
authors.initials: M
authors.lastname: Azhar
authors.affiliation: Laboratory for Simulation, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Greiner
authors.affiliation: Laboratory for Simulation, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany.
authors.forename: Jan G
authors.initials: JG
authors.lastname: Korvink
authors.affiliation: Laboratory for Simulation, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Kauzlarić