INTERACTION BETWEEN THE ION DIPOLE AND THE ION-INDUCED DIPOLE IN REACTIONS OF THE POLAR ION ARH3+

The reaction of the highly polar ion ArH3+ with the nonpolar neutrals Xe, Kr, CH4, CO, NO, O-2, and N-2 and with the polar neutrals SO2, H2O , NH3, CH3I, and C2H5I have been investigated in a selected ion flow d rift tube experiment at near thermal conditions. The rate coefficients obtained have typically 15%-35% larger values than the collisional li miting values k(L) and k(ADO) obtained by the Langevin and ADO (averag e dipole orientation) theory, respectively. These data are explained o n the basis of the interaction between the dipole of ArH3+ and the ion -induced dipole and the permanent dipole, respectively, of the neutral reactants. Rate coefficients for the reactions of H-3(+) with the abo ve neutrals were also obtained for comparison, as well as the zero fie ld mobility of ArH3+ in helium being (18.5+/-1.5) cm(2)/V s. The ion K rD3+ (KrH3+) was detected unambiguously for the first time. Its dissoc iation energy is larger than 0.29 eV which is the lower limit of the d issociation energy of ArH3+.