  Using the ORCA 5.0.2 software package we have simulated for a first time the
full tensors nJKL (K,L=X,Y,Z), describing n-bond J-coupling of nuclear spins
13C in H-terminated diamond-like clusters C10H16 (adamantane) and C35H36 as
well as in the cluster C33[NV-]H36 hosting the negatively charged NV- center.
We found that, in addition to usually considered isotropic scalar nJ-coupling
constant the anisotropic contributions to the nJ-coupling tensor are essential.
We have also shown that the presence of the NV center affects the J-coupling
characteristics, especially in the case of 13C-13C pairs located near the
vacancy of the NV center.
