The electric dipole moment of (NH3)2 for G: ‖K‖=1

From the results of Stark measurements on the (NH3)2 van der Waals complex formed in a molecular jet expansion, it was possible to determine the electric dipole moment for the G: ‖K‖=1 state. The partially quenched inversion in the complex gives rise to quadratic Stark effect. We find an electric dipole moment of ‖μ‖=(0.10±0.01) D in the ground state and an upper limit of 0.09 D for the dipole moment in the excited state. These small values give evidence that for the G: ‖K‖=1–1 states, the ‘‘antiparallel’’ (cyclic) structure is more likely than the hydrogen bonded one.