A Simple Method to Calculate Principal Values of Shielding Tensor

Inhomogeneous interactions, under slow rotation, generate a series of spinning sidebands, which contain information on their anisotropic tensors. In this paper, the flexible simplex search method for constraints was introduced to reconstruct the principal values of the anisotropic tensor by the intensities of a few spinning sidebands. The anisotropic parameters obtained from the spinning sidebands of Glycine powder at different spinning rate agreed well with the ones from Glycine crystal, i.e. their deviations were less than 3 ppm.