Nissan Spector

Identification of the spectra of Hf xlv, Ta xlvi, W xlvii, and Re xlviii isoelectronic to Ni i in laser- produced plasmas

The x-ray spectra in the range 5–8 A emitted from laser-produced plasmas of Hf, Ta, W, and Re were observed. Lines belonging to the 3d10 − 3d9 4f and 3d10 − 3d9 4p transitions, as well as the 3p63d10 − 3p53d10 4s and 3p63d10 − 3p53d10 4d transitions in the Ni-like isoelectronic sequence, were identified. In addition, the interpretation of some previously measured lines of the same sequence were revised.

Analysis of the free ion Nd3+ spectrum (Nd IV)

A recent breakthrough in the analysis of Nd IV resulted in the establishment of 37 energy levels of the ground configuration 4f3. We report here the completion to all 41 levels of this configuration. Wavelength measurements extended to 2800 A and in higher excitation conditions lead to the classification of 1426 lines involving the excited configurations 4f25d, 4f26p, 4f26s. Owing to configuration mixing between 5p64f26p and the core-excited 5p54f4, numerous 5p64f25d–5p54f4 transitions, normally dipole-forbidden, are observed. Altogether 111 odd parity levels and 121 even parity ones have been established. Their parametric least-squares fits have rms deviations of 91 cm−1 and 37 cm−1, respectively. The interaction 5p64f25d–5p54f35d has an impact on the 4f3–4f25d transition probabilities computed by means of the Cowan codes. Theoretical values of lifetimes are reported for all the even parity levels.

Analysis of the fourth spectrum of terbium (Tb iv)

The low-energy level structure of Tb3+ has been derived from spectra obtained with a sliding spark light source. The 7F ground term of the 4f8 configuration was found as well as all levels of the configurations 4f75d, 6s, and 6p built on the 8S7/2 core state of 4f7. Of the possible 51 lines connecting these levels, 48 were observed. Optimized radial parameters are given for the observed configurations. A value for the ionization energy of 39.37(0.10) eV is derived for Tb3+.

Analysis of the Spectrum of Neutral Erbium (Er i)

First results of a continuing analysis of Er i are given: 30 low levels belonging to 4f115d6s2 and other odd configurations, as well as 138 high levels of even parity are assigned J-values. More than 300 absorption lines are classified. The connection of the odd levels to the 4f126s2 configuration is established, using transitions in the infrared. The energy matrices in intermediate coupling for the subconfiguration f11(4I)d have been calculated and are given. The theoretical formulas were adjusted by a least-squares fit to 19 observed levels designated as 4f11(I4712,612)5d6s2 resulting in new values for 6 electrostatic and 2 spin-orbit interaction parameters. The rms error was 186 cm−1. Calculated percentage compositions in various coupling schemes show the J1 − j type to be the best for these levels.

Energy levels of 4f3 in the Nd3+ free ion from emission spectra

The emission spectrum of neodymium produced by vacuum spark sources was observed in the vacuum ultraviolet on two normal-incidence spectrographs. In an initial result, more than 550 lines have been identified as transitions from 85 4f 2 5d levels to 37 levels of the 4f 3 ground configuration in the free ion Nd 3+ . The levels 4f 34 F3/2 and 4 I11/2, responsible for the wellknown 1064 nm laser line, have respective positions of 11 698.57 ±0. 1c m −1 and 1897.07 ±0. 1c m −1 above the ground level 4 I9/2. The newly found levels of 4f 3 constitute the first isolated 4f N configuration (N > 2) and therefore enable checks of effective parameters that represent far configuration interaction. Slater parameters F k (4f, 4f) derived from Nd 3+ :LaCl3 are 3% to 5% smaller

Cr, Co, and Ni transitions isoelectronic to the Fe xxiv – Fe xvii lines around 11 Å in laser-produced plasma

The laser-produced plasma spectra of Cr, Co, and Ni observed between 9 and 14 A isoelectronic to the iron lines in the wavelength region 10.5–12 A are measured. Spectral lines belonging to many ionization stages fall in this wavelength region. Classification of most of these lines is given, based on isoelectronic extrapolation with comparison to other works on iron.

Transition probabilities for the 5p 4 6p–5p 4 6s array of Xe ii

Transition probabilities for the array 5p46p–5p46s of Xe ii are calculated using semiempirical intermediate coupling coefficients and ab initio relativistic transition integrals. Our results agree well with Andersen’s observations and also corroborate new measurements by Helbig and Boge, who introduce a correction to Boltzmann statistics due to “quasibound” states.

4fnl CONFIGURATIONS OF DOUBLY IONIZED CERIUM (Ce III)

A theoretical interpretation is given for the configurations of the type 4fnl of Ce iii. New values for radial parameters are obtained by least-squares. Percentage compositions in the appropriate coupling schemes are given for the energy levels. The rms error is less than 0.7% for most cases.

Configurations 4f 2 6s and 4f 2 6p in Doubly Ionized Pr

Energy parameters are given for the 4f26s and 4f26p configurations of Pr2+. An average agreement of better than 0.5% of the total configuration spread is obtained between the predicted and observed energy levels, in both cases. Designations in (LS)J – j coupling are given.

Spectrum and energy levels of the Nd4+ free ion (Nd V)

The spectrum of neodymium excited by a sliding spark source was photographed on two vacuum ultraviolet normal-incidence spectrographs. About 250 lines attributed to Nd V, hitherto unknown, have been identified. The analysis of this spectrum established all the energy levels of the configurations 4f2, 4f5d, 4f6s and 4f6p (except for 4f2 1S0). Altogether, 48 known levels classify about 160 lines. Their theoretical calculation includes a least-squares fit with an rms error of 28 cm−1 for the even-parity levels and 26 cm−1 for the odd-parity ones, as well as the best values for relevant radial interaction parameters. In particular, interactions with the core-excited configurations 5p54f3 and 5p54f25d are discussed. Intensities derived from phosphor image plates are used to estimate an effective temperature in the spark of Teff=3.6 eV.