O Vogel

Accurate Experimental Lifetimes of Excited Levels in Nd II

Radiative lifetimes of 24 levels in Nd II have been measured with a laser-ion beam technique using intracavity excitation. Of the lifetimes, 8 were measured with current normalization and 16 with an improved experimental setup using fluorescence light normalization. 11 of the levels have not been measured previously. Several levels were found to have a different lifetime than earlier reported. The measured lifetimes were used to correct old gf-values deduced from arc spectra. These new gf-values together with 17 equivalent widths, obtained from high resolution tracings of the solar disc center spectrum, were used in a solar photosphere abundance analysis which confirmed our old Nd abundance value.

Radiative Lifetimes of Excited Levels in the Homologous Ions Ar II, Kr II and Xe II

Radiative lifetimes of nine of the levels np 4P5/20, np 4D7/2,5/20 and np 2D5/20 in the homologous ions Ar II (n = 4), Kr II (n = 5) and Xe II (n = 6) have been measured with the beam-laser method. The measured lifetimes are compared with lifetime values from other experimental and theoretical works and a thorough discussion of the discrepancies between the results obtained with different techniques is made. Older measurements of transition probabilities are put on an accurate scale using the new lifetime values. The f-values of some strong transitions from levels in the np configuration in Ar II, Kr II and Xe II are compared and are found to be approximately equal.

Radiative lifetimes in Sm II and the solar samarium abundance

Radiative lifetimes of 18 levels in Sm II have been measured using the beam-laser technique. For 11 of the levels the lifetimes have not been measured before. The measured lifetimes were used to put old relative gf-values obtained from emission measurements on an absolute scale. These absolute gf-values were subsequently used in a determination of the solar photospheric abundance of samarium by means of synthesis of the solar spectrum. The estimated solar samarium abundance is ASm = 1.02 ± 0.11 dex.

Radiative lifetimes in Nd II and the solar neodymium abundance

Radiative lifetimes of the eight levels 4f4(5I)6p 6K9/2,11/2,13/2,15/2,17/2,19/20, 4f4(5I)6p (27 448)13/20 and 4f4(5I)6p (29 027)17/20 in Nd II were measured with a laser-ion beam technique using intracavity excitation. The lifetimes of three of the levels have not been measured previously. Four lifetimes were found to be significantly shorter than earlier reported. The measured lifetimes were used to correct old gf-values deduced from arc spectra. The improved gf-values were subsequently used in a solar photosphere abundance analysis based on modern solar models and high resolution solar spectra. The Nd abundance was found to be almost twice as large as that previously reported from photosphere analysis and in very good agreement with meteoritic data. The abundance is ANd = 1.47 ± 0.07 on the scale where ANd = log (NNd/NH) + 12.

Radiative lifetimes in Y II

Radiative lifetimes of the eight levels y 3P0,1,20, 1D20, z 3D1,2,30 and z 1F30 in Y II have been measured with the beam-laser technique. In comparison with previously reported data, our lifetime values have greater accuracy and, for some of the levels, the lifetimes differ from previous results.

Radiative lifetimes of some excited levels in Eu II

Radiative lifetimes of the six levels 6p3/2(7/2, 3/2)2, 3, 4, 5 and 6p1/2(7/2, 1/2)3, 4 in Eu II are measured with a laser-ion beam technique using intracavity excitation and tandem pumping.

Radiative Lifetimes of Some Excited Levels in Sc II

Radiative lifetimes of the six levels 6p3/2(7/2, 3/2)2, 3, 4, 5 and 6p1/2(7/2, 1/2)3, 4 in Eu II are measured with a laser-ion beam technique using intracavity excitation and tandem pumping.

Atomic physics with ECR ion source in Uppsala

An ECR (Electron Cyclotron Resonance) ion source has recently been installed in Uppsala at The Svedberg Laboratory. The ion source will be used both as an injector for a K = 200 synchrocyclotron and to provide ion beams for atomic physics experiments. So far three different research programs in atomic physic are planned and a laboratory in connection to the source is presently under construction. After a short description of the ion source and the atomic physics laboratory, the three programs• Charge transfer mechanisms in slow collisions (J Nordgren)• Optical spectroscopy and laser excitation of doubly and multiply ionized atoms (0 Vogel)• Sputtering of organic solids with slow multi-charged ions (B Sundquist)are briefly presented.

Lifetimes in K ii with the beam-laser method

The lifetimes of the 3p54p3D1, 3D2, 3D3, and 1D2 levels of singly ionized potassium, K ii, have been measured using the beam-laser method (7.0 ± 0.3, 7.2 ± 0.3, 6.89 ± 0.15, and 7.7 ± 0.4 nsec, respectively). The lifetimes are 10 to 25% shorter than previous beam-foil lifetimes. Improved transition probabilities are recommended for some transitions in K ii.