Computer simulations in solid‐state NMR. III. Powder averaging

As the final part in a series of articles on numerical simulations in solid‐state NMR (Concepts Magn Reson 17A: 117–154, 2003 and Concepts Magn Reson Part A 18A: 1–23, 2003), aspects of simulations of NMR responses from powders are discussed. The underlying equations for powder averaging are derived, and it is demonstrated how powder averages may be estimated numerically. Orientational symmetry in solid‐state NMR is summarized and exploited to achieve more efficient calculations. Explicit computer code in C/C++ is given for simulation of NMR spectra from powders containing (1) two homonuclear spins‐1/2 in a static sample and (2) a heteronuclear two spin‐1/2 system under magic‐angle‐spinning conditions.