Calculation of the diamagnetic spin-orbit contribution to the nuclear spin-spin coupling tensors in the water molecule.

The diamagnetic spin-orbit contribution to the nuclear spin–spin coupling constants of water has been calculated employing SCF wave functions of increasing accuracy. The results demonstrate that this term is small in the case of direct O–H average coupling constants. On the other hand, a significant contribution ([approximately-equal-to]−7 Hz) to geminal H–H coupling constant is found. The theoretical results are slightly affected by the characteristics of the basis set employed in the calculations.