Photoionization of the neon–rare gas dimers NeAr, NeKr, and NeXe

Abstract

The relative photoionization cross sections for the heteronuclear neon–rare gas dimers NeAr, NeKr, and NeXe were measured at a wavelength resolution of 0.15 Å for NeAr and 0.28 Å for NeKr and NeXe in the energy region between the molecular ionization threshold and the atomic 2P01/2 ionization limit of the heavier rare gas atom. The dimer ionization potentials are 15.685±0.004 eV for NeAr, 13.950±0.003 eV for NeKr, and 12.094±0.004 eV for NeXe. Combining these values with the known values of the atomic ionization potentials and the neutral ground state dissociation energies yields values of the A 2Σ+1/2 ionic ground state dissociation energies of 0.079±0.004 eV for NeAr, 0.055±0.003 eV for NeKr, and 0.041±0.004 eV for NeXe. Molecular Rydberg structure, which shows strong similarities to the atomic structure in the region of the autoionizing Beutler–Fano resonances, has been partially analyzed in terms of Rydberg series converging to the B 2Π1/2 state of the dimer ion. Vertical binding energies for the individual Rydberg states were determined based on the assumption that the Rydberg states dissociate to a neon atom in the 1S0 ground state plus a rare gas atom in an ns′[1/2]01 or nd′[3/2]01 excited state. Values of the vertical binding energies of the B 2Π1/2 ionic state were determined from the series limits and are 0.022±0.002 eV for NeAr, 0.018±0.004 eV for NeKr, and 0.014±0.002 eV for NeXe.