Showing results 21 to 26 of 26
  Singlet-triplet excitation ratios in Ne III, Ar III and N II under ion impact; Garnir, Henri-Pierre  ; Dumont, Paul-Dominique et alin European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2001), 15 Peculiar properties of ion-atom collision systems, in particular deviations from statistical populations of singlet and triplet levels, can be studied by optical spectroscopy.We have extended earlier ... [more ▼] Peculiar properties of ion-atom collision systems, in particular deviations from statistical populations of singlet and triplet levels, can be studied by optical spectroscopy.We have extended earlier studies by VUV spectroscopy of a number of collision systems at various collision energies in the 0.01-MeV/nucleon to 1-MeV/nucleon range, involving H+ 2 , H+, He+, He2+, Ne+, Ar+, and N+ 2 as projectiles and Ne, Ar, and N2 as target gases. Statistically signi cant deviations of the relative intensities of singlet and triplet lines from simple ratios are observed in the displaced terms of the valence shell of Ne III, corroborating and extending earlier work. For Ar III, the energy dependences of singlet-to-triplet excitation ratios are very different for dff erent projectiles. For NII, in contrast, all observed line ratios are practically independent of the projectile energy. [less ▲] Detailed reference viewed: 14 (2 ULg)Lifetimes of metastable state in Sr IIBiémont, Emile ; ; et alin European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2000), 11 Detailed reference viewed: 2 (0 ULg)Atomic Lifetimes and Transition Probabilities in Boron-like (Na VII) and Beryllium-like (Na VIII) Sodium IonsTordoir, Xavier ; Biémont, Emile ; Garnir, Henri-Pierre et alin European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (1999), 6 A critical compilation and extended analysis of the Ne IV spectrum; Bastin, Thierry ; Biémont, Emile et alin European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (1999), 7 Since Moore published her well-known tables of atomic and ionic energy levels (in 1949-1951), the number of observed lines of the light atoms and their ions has grown signifi cantly. The lack of complete ... [more ▼] Since Moore published her well-known tables of atomic and ionic energy levels (in 1949-1951), the number of observed lines of the light atoms and their ions has grown signifi cantly. The lack of complete and consistent up-to-date tables of spectral lines and energy levels, particularly of the neon-ions spectra, notably reduces possibilities of interpretation of astrophysical and laboratory spectra. In the present paper, all optical spectral lines of Ne IV observed in 24 previous works have been systematised together with recent observations made by means of the beam-foil method at Liège University. As a result of our extended analysis of the whole set of available data, 35 new energy levels have been found and 90 newly classi ed spectral lines have been listed for the Ne IV spectrum, only a few of them having been reported previously. A complete table of observed and classi ed spectral lines has been built, and the list of optimised energy levels has been derived from it in a consistent way. A new, improved, ionisation potential of Ne IV has been deduced from the experimental data. [less ▲] Detailed reference viewed: 10 (2 ULg)A critical compilation and extended analysis of the Ne V spectrum; Bastin, Thierry ; Biémont, Emile et alin European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (1999), 7 Previous works devoted to the Ne V spectrum are very fragmentary and yield a rather controversial picture of this ion. A lot of unidentifi ed lines are still reported in these multiple studies. In the ... [more ▼] Previous works devoted to the Ne V spectrum are very fragmentary and yield a rather controversial picture of this ion. A lot of unidentifi ed lines are still reported in these multiple studies. In the present paper, Hartree-Fock calculations and least-squares fi ts over the whole set of the available data (including the most recent ones) have been performed. As a result, a comprehensive view of the Ne V spectrum is presented. 10 new energy levels and 40 newly classi fied lines are proposed. An improved value of the ionisation potential of Ne V is also proposed. [less ▲] Detailed reference viewed: 13 (4 ULg)Determination of radiative lifetimes of neutral sulphur by time-resolved three-photon VUV laser spectroscopy; ; et al in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (1998), 2 Detailed reference viewed: 4 (1 ULg)
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