Singlet-triplet excitation ratios in Ne III, Ar III and N II under ion impact

in 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 ▲]

Beam-gas excitation of Ar III 3s3p5 singlet and triplet terms

Poster (2001)

A critical compilation and extended analysis of the Ne V spectrum

in 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 ▲]

Ne VI spectrum

in Journal of the Optical Society of America. B, Optical Physics (1999), 16

On the basis of all the available observations of the Ne VI spectrum, particularly the new beam-foil spectra obtained at Liège University, approximately 50 new line assignments are proposed and ... [more ▼]

On the basis of all the available observations of the Ne VI spectrum, particularly the new beam-foil spectra obtained at Liège University, approximately 50 new line assignments are proposed and approximately 30 new energy levels are determined in Ne VI. All known energy levels have been improved, and a new value is proposed for the ionization potential. The new line identifications are supported by Hartree–Fock calculations combined with parametric fitting of energies and transition rates. [less ▲]

Extended Analysis of the Highly Ionized Neon Spectra

Poster (1999)

The Spectra Ne IV, Ne V ans Ne VI

Conference (1998)

Automatic external filling for the ion source gas bottle of a Van de Graaff accelerator

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (1997), 129

We describe a fully automatic system we developed to fill, from an external gas bottle, the ion sourer terminal gas storage bottle of a 2 MV Van de Graaff accelerator without depressing the 25 bar ... [more ▼]

We describe a fully automatic system we developed to fill, from an external gas bottle, the ion sourer terminal gas storage bottle of a 2 MV Van de Graaff accelerator without depressing the 25 bar insulating gas. The system is based on a programmable automate ordering electropneumatical valves. The only manual operation is the connection of the external gas cylinder. The time needed for a gas change is reduced to typically 15 min (depending on the residual pressure wished for the gas removed from the terminal bottle). To check this system we study the ionic composition of the ion beam delivered by our accelerator after different gas changes. The switching magnet of our accelerator was used to analyse the ionic composition of the accelerated beams in order to verify the degree of elimination of the previous gases in the system. (C) 1997 Elsevier Science B.V. [less ▲]

External gas filling for the ion source gas bottle of an accelerator Van de Graaff based on a micro-progammable

Poster (1996)

Importance of the dye Laser Tuning on Beam-Foil-Laser Effect

Poster (1996)

Beam-foil spectroscopy of Ne and new level determinations in Ne IV and V

Poster (1996)