The open-source Python package, mrsimulator (https://mrsimulator.readthedocs.io), is presented as a simple-to-use, versatile, fast, and open-source library capable of simulating one- and higher-dimensional NMR spectra under static, magic-angle, and variable-angle conditions. High benchmarks in spectral simulations are achieved by limiting simulations to situations where analytical solutions are available for transition frequencies and coherence transfers between transitions. This approach is generalized to multi-dimensional NMR spectra simulations using concepts from our symmetry pathway approach for describing multi-pulse NMR experiments. mrsimulator supports the simulation of uncoupled and coupled spin systems with nuclei of arbitrary spin. Support of coupled spin systems, however, is limited to those well described by inhomogeneous Hamiltonians. That is, we avoid simulations that involve strong homogeneous interactions as defined by Maricq and Waugh, i.e., interactions with Hamiltonians that do not commute with each other at different times during the experiment. Fortunately, this constraint only prevents mrsimulator from modeling spectra of a small fraction of popular solid-state NMR methods. The efficiency gains with this approach are essential for modeling spectra of non-crystalline materials where subspectra from thousands of spin systems are needed for accurate modeling. Illustrative examples in the presentation will include the use of mrsimulator in the analysis of 2D NMR spectra of silicate glasses.
