Jean Blaise

Energy levels of neutral atomic uranium (Ui)

High-resolution grating and Fourier transform spectroscopy measurements, using hollow-cathode and electrodeless discharge lamp sources, have resulted in a list of 92000 lines of Ui and Uii. The wave-number accuracy is about 0.003 cm−1. With this list and new Zeeman structure, isotope-shift, and 233U hyperfine-structure spectrograms, we have found 500 new Ui levels. We now know 1240 even levels between 7020 and 42000 cm−1 and 360 odd levels up to 38000 cm−1. All levels expected to lie below 10000 cm−1 have been found. Levels of five odd configurations (f3ds2, f3d2s, f4sp, f3ds8s, f4dp) and seven even configurations (f4s2, f2d2s2, f3s2p, f3dsp, f4ds, f3d2p, f3ds8p) are now known.

Revised Interpretation of the Spectrum of Singly-Ionized Neodymium (Nd II)

Because of the confusion between two low odd levels 1218 cm-1 apart, the complete system of levels of Nd II built on the core f3 had to be revised with the help of the 144Nd-150Nd isotope shift. The lowest odd level f3d2 6M13/2 is now at 8009.810 cm-1, 96 levels have been shifted and 126 new levels have been found. The new identifications rely upon parametric studies of the sub-configurations 4f35d6s + 4f3(4I)5d2 + 4f4(5I)6p (115 interpreted levels) and 4f3(4I)5d6p + 4f3(4I)6s6p (124 interpreted levels).

Generalized Parametric Study of 5fN and 5fN7s Configurations

The parametric studies of 5fN and 5fN7s configurations by application of both Slater-Condon theory and the generalized least-squares method to the whole sequence of actinides has led to the simultaneous interpretation of 72 levels in first spectra (5fN7s2) and of 112 levels in second spectra (5fN7s). The determination of the N-dependence of various electrostatic parameters of the 5fN core improves the reliability for prediction of missing configurations. Revised interpretations and new energy levels are reported in a number of spectra.

Energy levels and isotope shifts for singly ionized uranium (U ii)

New uranium hollow-cathode Fourier-transform spectra have been recorded between 1800 and 42 000 cm−1. Combined with earlier visible and ultraviolet spectra, these have led to 354 odd levels and 809 even levels of singly ionized uranium (U ii) belonging to four odd and six even configurations. High-resolution Fourier-transform spectra of an electrodeless discharge lamp containing 238UI4 and 234UI4 were used to measure splittings of more than 800 isotopic U ii doublets to an accuracy of ~0.001 cm−1. From these transition isotope shifts 114 odd- and 397 even-level isotope shifts were determined.

Progrès Récents dans l'Interprétation des Configurations 4fN(5d + 6s) des Lanthanides II. Etude Paramétrique des Configurations

An extensive study of the configurations 4fN(5d + 6s), using the methods of Racah, which included the configuration interaction for these two configurations and effective electrostatic parameters for the 4f-5d interaction leads to an improved agreement between observed and calculated energies for seven spectra and to find new energy levels for PrIII, PrII and TmII. Because of the regularities of the radial parameters either in the isoelectronic series or in the same stage of ionization sequences, we are able to predict the energy differences of many levels for ErIII and HfV.

Term analysis of the spectrum of neutral neptunium (Np I)

We have measured 6096 Np wavelengths with the 9 m Paschen-Runge spectrograph at Argonne and the Fourier transform facilities at Aime Cotton, of which 40% have been classified as transitions between 130 even levels and 329 odd levels. Most of the even levels and half of the odd levels have been identified by hyperfine structure and Zeeman data. The ground configuration is 5f46d7s2; the next configuration, 5f57s2, starts at 2831 cm−1. The low levels of 5f46d27s, 5f36d27s2, and 5f46d7s7p have been identified, and parameter fits made for 5f46d7s2 and 5f47s27p.

Energy levels and transition probabilities in doubly-ionized erbium (Er III)

The spectrum of Er III reported by Becher (1966) was reanalysed with the support of new predictions of energies and transition probabilities. The number of energy levels was increased from 45 to 115, including two levels of 4f117s and the levels 3F3, 3F2 and 1G4 of the ground configuration 4f12. All 470 classified lines are reported with transition probabilities for most of them. Several of these lines had not yet been attributed to Er III in the spectrum of the star HR465.

Configuration mixing in singly-ionized platinum group elements. I, Low odd configurations of Hf II, Ta II and W II

The odd energy levels of Hf II, Ta II and W II have been investigated by means of the Slater-Condon parametric method. This led us to elimination of fortuitous levels reported in earlier analyses, to revision of J-values and the finding of 23 new levels in Ta II. The configuration mixing is very strong in the groups 5dN−16s6p + 5dN−26s6p + 5dN−36s26p, the latter configuration being generally unrecognizable. Very few low odd levels are still unknown in these spectra.

The i.r. spectrum of berkelium-249

Abstract The spectrum of 249 Bk, excited in an electrodeless lamp, has been recorded between 3700 and 12,000 cm −1 on a Fourier-transform spectrometer. The strongest 90 lines are listed along with the classification for 77 of them. The lowest levels of the 5f 9 6d7s, 5f 9 7s7p, 5f 9 7s8s, 5f 8 6d7s 2 , 5f 8 7s 2 7p and 5f 8 6d7s7p configurations of Bk I and of the 5f 9 6d and 5f 9 7p configurations of Bk II have been identified. Lists of the energies and hfs data of the Bk I levels involved in the i.r. transitions are also included.

The i.r. spectrum of curium-244☆

Abstract The spectrum of curium-244 has been observed on the high resolution Fourier-transform spectrometer at Laboratoire Aime Cotton. An electrodeless lamp containing 50 μg of CmI 3 was run for 12 hr and 800,000 points were taken. A total of 1743 lines have been ascribed to curium and 87% of the lines have been assigned to transitions between known energy levels.