Collision-based spectroscopy of Xe VIII Rydberg states

The photon emission from 10q keV Xe-q+ + T (q = 7, 8; T = He, Ar, Na) collisions has been recorded in the 35-800-nm wavelength region. Especially in the T = Na spectra we observed many unreported lines, of which 68 were ascribed to Xe VIII transitions involving Rydberg states. As a result of this, we established 32 new energy levels and revised the energies of 6 previously reported levels. The Xe VIII ionization energy 854 755 +/- 33 cm(-1) was determined with improved accuracy. Furthermore, we derived Ritz formula coefficients for the observed Rydberg series and the core dipole and quadrupole polarizabilities. The analysis was supported by Hartree-Fock calculations. (C) 1996 Optical Society of America.