Ways of specifying NMR interactions
Nuclear chemical shift	Use inter.zeeman.scalar for isotropic chemical shifts, inter.zeeman.matrix for anisotropic chemical shift tensors supplied as matrices, or inter.zeeman.eigs & inter.zeeman.euler for anisotropic chemical shift tensors specified as eigenvalues and Euler angles.
Inter‐nuclear J‐coupling	Use inter.coupling.scalar; couplings that are specified multiple times, for example, between spins 1 and 2, and then again between spins 2 and 1, will be added together.
Inter‐nuclear dipolar coupling	Use inter.coordinates if nuclear coordinates are known (they will be converted into a dipolar interaction matrix internally), or inter.coupling.matrix for dipolar coupling supplied as a matrix, or inter.coupling.eigs & inter.coupling.euler for dipolar interactions supplied as eigenvalues and Euler angles.
Nuclear quadrupolar coupling	Best specified as an “interaction” of the nucleus with itself. Use inter.coupling.matrix or inter.coupling.eigs & inter.coupling.euler for quadrupolar interactions specified as eigenvalues and Euler angles.