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Energies and Auger widths of high-lying doubly-excited states 1s23 lnl′ ( n = 3-6) for Be-like neon are calculated using a saddle-point variational method and saddle-point complex-rotation method. The relativistic corrections and mass polarization are obtained with first-order perturbation theory. The configuration structure of the high-lying doubly-excited series is checked by relativistic perturbation corrections. The oscillator strengths and radiative transition probabilities are also calculated. Our results of energies and Auger widths are compared with the available theoretical results in the literature. Auger channel energies are compared with those from high-resolution electron spectroscopy. Excellent agreement is obtained in each state. [ABSTRACT FROM AUTHOR]

The relativistic corrections to the theoretical oscillator strengths of light elements such as helium are typically less than 0.1% and usually are ignored. However, they can be important for comparisons with the most accurate experiments, and they rapidly increase in magnitude with increasing nuclear charge. We have begun with the spin-forbidden electric-dipole transitions of neutral helium, using calculations consisting of (1) extremely accurate wave functions without relativistic corrections for both infinite and finite nuclear mass, (2) spin-changing matrix elements through the perturbations of the wave functions by the spin-orbit and spin-other-orbit Breit operators, (3) the use of pseudostates in the sums over all the intermediate states including the continuum, and (4) the inclusion as perturbers of the 1S0 and 3S1 states the pseudostates corresponding to the doubly excited npn′p 3P0e and npn′p 1P1e terms, respectively. As examples of these calculations, we present oscillator strengths for the transitions 1 1S0-2 3P1, 2 1S0-2 3P1, 2 3S1-2 1P1, 2 1P1-3 3D1,2, and 2 3P1,2-3 1D2. Les corrections relativistes aux forces d'oscillateur théoriques d'éléments légers comme l'hélium sont typiquement plus petites que 0.1% et sont généralement ignorées. Cependant, elles peuvent être importantes pour comparer avec les valeurs expérimentales les plus précises et elles augmentent rapidement avec la charge nucléaire. Nous débutons avec les transitions dipolaires électriques spin interdites dans l'hélium neutre, à l'aide de calculs qui reposent sur, (1) des fonctions d'onde extrêmement précises sans correction relativiste pour des masses nucléaires infinies et finies, (2) des éléments de matrice de changements de spin via les perturbations de la fonction d'onde causées par les opérateurs de Breit de spin-orbite et de spin-autre orbite, (3) l'utilisation de pseudo états dans la somme sur tous les états intermédiaires, incluant le continuum et (4) l'introduction, comme agents perturbant les états 1S0 et 3S1, des pseudo états correspondant aux termes doublement excités npn′p 3P0e et npn′p 3P1e respectivement. Comme exemples de nos calculs, nous présentons les forces d'oscillateur pour les transitions 1 1S0-2 3P1, 2 1S0-2 3P1, 2 3S1-2 1P1, 2 1P1-3 3D1,2 et 2 3P1,2-3 1D2. [ABSTRACT FROM AUTHOR]

We measured the spontaneous-emission branching ratios of 69 levels in Sm II selectively populated via single-frequency laser excitation of a 10 keV ion beam. The levels studied had term energies up to 29 600 cm–1, and decay branches with spontaneous emission in the range 250–850 nm were detected. The experimental accuracy was in the range of 10%. We used these branching ratios along with our previously determined radiative lifetimes to infer transition probabilities and oscillator strengths for 608 transitions in the wavelength range 363–771 nm, which are useful for stellar abundance determinations.PACS Nos.: 32.70.Cs, 95.30.Ky [ABSTRACT FROM AUTHOR]