On the relativistic theory of nuclear spin-spin coupling constants

Time-reversal symmetry is exploited to halve the computational effort for the calculation of nuclear spin-spin coupling constants in the framework of the relativistic analogue of Ramsey's theory. The derivation is given for quaternionic relativistically parameterized extended Hückel (QATREX) wavefunctions, but the arguments used apply to any quantum-chemical method which generates Kramers pairs. Applications to selected heavy-element fluorides MF n (n = 2, 4, 6) are given based on charge-iterated REX calculations.