The nuclear-quadrupole-induced dipole moment of HD

We calculate in a simple MO way the dipole moment induced in HD by the nuclear quadrupole of the deuteron, as a function of the internuclear separation. We find a reversal of the direction of the dipole with increasing internuclear separation, for which we note indirect experimental evidence. As a check on the accuracy of our result we also calculate the electric field gradient induced at the D nucleus by an external electric field, per unit external field, which for exact theory would be exactly the same function. The form of the function so obtained is indeed similar - although not identical - to that for the dipole moment. The dipole moment at the equilibrium internuclear separation is ≈0.075 atomic units per unit quadrupole moment, directed H-→D+. (For the measured quadrupole moment of the deuteron, this is ≈2×10-11 D.) However, we find the induced field gradient at the deuteron for this separation to be 0.094 atomic units per unit external field, in the opposite direction. © 1988