“…To describe these observations we have used standard spin-Hamiltonians (see, e.g. [14,15]) of the ground 2 E g and the excited 2 E U doublet states of the tronic spin operators of the center, A, so^ are the SO coupling constants in the ground and excited states), second term is the Jahn-Teller interaction (see [15,16] for details), the third term H z = qy L L • B + y 5 S • B takes into account the Zeeman interaction of L and S with external magnetic field B (Yz =M-B/^» YS = 2ji B /ft are orbital and electron gyromagnetic ratios, |i B is the Bohr magneton, q is the Ham quenching factor) and the last term H hfi = S • A • I which was absent in [15,16] we added to describe hfi of electronic spin S = 1/2 of the SiV~ center with the nuclear spin / = 1/2 of the 13 C atom located somewhere in the diamond lattice (here A KL is the hfi matrix which was calculated for the all possible positions of the nuclear 13 C spin in the C 128 [SiV-]H 98 cluster).…”