THE COLLISION-INDUCED ELECTRIC-DIPOLE MOMENT OF H(N=2) IN H-HE, NE AND AR COLLISIONS

The collision-induced electric dipole moment of H(n=2) in H(1 s)-Ne and H(1 s)-Ar collisions was measured in an energy range of 1 to 25 keV. For these systems we observe a positive electric dipole moment which corresponds to an electron lagging behind the proton. This behaviour is in contrast to recent measurements for the H-He systems, where a negative dipole moment corresponding to an electron moving in front of the proton was observed. A simple explanation for this difference is given.