Analysis of the (5d8 + 5d76s)–5d76p transitions of seven-times-ionized bismuth: Bi VIII

1995 ◽  
Vol 73 (1-2) ◽  
pp. 63-73
Author(s):  
R. R. Kildiyarova ◽  
Y. N. Joshi ◽  
M. A. Lumsden ◽  
A. J. J. Raassen
Keyword(s):  
Least Squares ◽  
Wavelength Region ◽  
Normal Incidence ◽  
Isoelectronic Sequence ◽  
Scaling Factors ◽  
Energy Parameters ◽  
Transition Array

The spectrum of bismuth was photographed in the 400–1200 Å (1 Å = 10−1 m) wavelength region on a 3 m normal incidence spectrograph using a triggered spark source. The 5d8, 5d76s, and 5d76p configurations of Bi VIII were analysed. The missing 1S0 level of the 5d8 configuration, 27 of 38 levels of the 5d76s configuration, and 30 additional levels of the 5d76p configuration were established. One previously identified level at 338 016 cm−1 (J = 3) was revised to 338 701 cm−1. Two hundred and sixty-three lines were classified in the 5d76s–5d76p transition array, and 26 additional lines were classified in the 5d8–5d76p transition array. The least-squares-fitted parametric calculations interpret the observed spectrum satisfactorily. The scaling factors of the energy parameters were compared in the isoelectronic sequence from Au IV to Bi VIII.

A Theoretical Survey of 4s–4p and 4p–4d Transitions in Nickel-Like Ions

1988 ◽  
Vol 102 ◽  
pp. 299-302
Author(s):  
J.-F. Wyart
Keyword(s):  
Ab Initio ◽  
Least Squares ◽  
Generalized Least Squares ◽  
Potential Method ◽  
Current Interest ◽  
Isoelectronic Sequence ◽  
Energy Parameters ◽  
Least Squares Fit ◽  
Charge States ◽  
A Current

AbstractMulticharged ions in the isoelectronic sequence of nickel have a current interest, due to possible population inversions occuring between excited levels. The identification of 4s-4p and 4p-4d transitions was recently extended up to Mo XV, owing to new experiments performed at I.S.A.N., Troitsk (USSR), and to the subsequent interpretation of the first excited configurations by means of the Slater-Condon method and generalized least squares fit of energy parameters along a sequence. For predicting transitions in higher charge states, the same configurations have been studied ab initio by using the relativistic parametric potential method and selected transitions involving short-lived lower levels are given for 14 ions in the sequence from Sr XI to Eu XXXVI.

Revised analysis of the Zn VI spectrum

1994 ◽  
Vol 72 (5-6) ◽  
pp. 193-205 ◽  
Author(s):  
G. J. van het Hof ◽  
Y. N. Joshi ◽  
A. J. J. Raassen
Keyword(s):  
Least Squares ◽  
Wavelength Region ◽  
Grazing Incidence ◽  
Operator Technique ◽  
Least Squares Fitting ◽  
Extensive Data ◽  
Orthogonal Operator ◽  
Transition Array

The spectrum of zinc was photographed in the 100–300 Å (1 Å = 10−10 m) wavelength region on a 10.7 m grazing-incidence spectrograph. On the basis of these precise and extensive data the 3d7–3d64p transition array of Zn VI was reanalysed. All 19 levels of the ground configuration 3d7 were confirmed but the level values were revised. Out of the 161 levels of the 3d64p configuration reported earlier, 10 levels were rejected and 16 new levels were established thus totalling the known levels to 167. The number of the classified lines is 538, almost doubling the previous number. The least-squares-fitting parametric calculations adequately interpret the observed spectrum. The 3d7 configuration was also described by an orthogonal operator technique.

The analysis of the 5s25p2, 5s5p3, 5s25p5d, and 5s25p6s configurations of Te III

1992 ◽  
Vol 70 (9) ◽  
pp. 740-744 ◽  
Author(s):  
Y. N. Joshi ◽  
A. Tauheed ◽  
I. G. Davison
Keyword(s):  
Configuration Interaction ◽  
Ground State ◽  
Wavelength Region ◽  
Normal Incidence ◽  
Configuration Interaction Calculations ◽  
Transition Array

The spectrum of tellurium was photographed in the wavelength region 400–2000 Å (1 Å = 10−10 m) on a 3 m normal incidence spectrograph. The new measurements and configuration interaction calculations lead to major revisions in the earlier analysis of Te III. For the ground state 5s25p2, all but one of the previously known levels have been confirmed. Out of the 26 levels belonging to the three excited configurations, viz. 5s5p3, 5s25p5d, and 5s25p6s, 14 levels have been confirmed, 4 have been rejected, and for 8 of the levels, either the designation, J value or configuration assignments have been revised. Configuration interaction calculations were carried out to interpret the observed spectrum. Seventy-two lines have been classified in the 5s25p2 − (5s5p3 + 5s25p5d + 5s25p6s) transition array.

4d75s–4d75p Transitions in Ag IV

1983 ◽  
Vol 61 (1) ◽  
pp. 36-39 ◽  
Author(s):  
Th. A. M. vanKleef ◽  
Y. N. Joshi
Keyword(s):  
Least Squares ◽  
Wavelength Region ◽  
Normal Incidence ◽  
Hartree Fock ◽  
Least Squares Fit

The spectrum of silver was photographed in the wavelength region 400–2300 Å on a variety of spectrographs including a 10.7 m normal incidence vacuum spectrograph. The sources used were a sliding spark and a triggered spark. On the basis of these observations, 12 missing levels of the 4d75p configuration and all levels of the 4d75s configuration have been established. The least squares fit and Hartree–Fock calculations support the analysis. Seven hundred and twelve additional lines have been classified in this spectrum, 40 of which are doubly classified and four are trebly classified.

The 5s25p4 – (5s5p5 + 5p36s) transitions in Ce VII and 5s25p3 4S – 5s5p4 4P transitions in Ce VIII

2008 ◽  
Vol 86 (5) ◽  
pp. 714-725
Author(s):  
A Tauheed ◽  
Y N Joshi
Keyword(s):  
Least Squares ◽  
Configuration Interaction ◽  
Wavelength Region ◽  
Normal Incidence ◽  
Grazing Incidence ◽  
Spectral Lines ◽  
Hartree Fock ◽  
Resonance Transitions

The spectrum of cerium was photographed in the 300–1230 Å wavelength region on a 3~m normal incidence spectrograph at the Antigonish laboratory and on a 3 m grazing incidence spectrograph at the Institute of Spectroscopy laboratory in Troitsk in the 250–350 Å region. The 5s25p4 – (5s5p5 + 5p36s) transitions of six-time ionized cerium (Ce~VII) were identified. All levels of these three configurations have been established. Forty spectral lines have been classified in the Ce VII spectrum. Configuration interaction Hartree–Fock calculations and least-squares-fitted parametric calculations were used to interpret the observed spectrum. In the Ce VIII spectrum, we have identified the 5s25p3S3/2 – 5s5p4P1/2, 3/2, 5/2 resonance transitions. PACS Nos.: 32.30.Jc, 32.30.–r

Broadband multilayer-coated normal incidence blazed grating with ~10% diffraction efficiency through the 13-16 nm wavelength region

2009 ◽  
Vol 34 (6) ◽  
pp. 818 ◽  
Author(s):  
Lichao Zhang ◽  
Hui Lin ◽  
Chunshui Jin ◽  
Hongjun Zhou ◽  
Tonglin Huo
Keyword(s):  
Diffraction Efficiency ◽  
Wavelength Region ◽  
Normal Incidence ◽  
Blazed Grating

Revised and extended analysis of the 3d10nl configurations in As V, Se VI, and Br VII

1986 ◽  
Vol 64 (3) ◽  
pp. 330-333 ◽  
Author(s):  
Y. N. Joshi ◽  
Th. A. M. Van Kleef
Keyword(s):  
Wavelength Region ◽  
Normal Incidence ◽  
Extended Analysis

The spectra of arsenic, selenium, and bromine were photographed in the wavelength region 450–2000 Å on 6.65- and 3-m normal-incidence spectrographs using a triggered spark source. The new observations have led us to revise and extend the As V, Se VI, and Br VII spectra.

The 4d95p transitions in the tenth spectrum of cesium, Cs X

1991 ◽  
Vol 69 (1) ◽  
pp. 24-25 ◽  
Author(s):  
Y. N. Joshi ◽  
B. Arcimowicz
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Least Squares ◽  
Wavelength Region ◽  
Hartree Fock

The spectrum of cesium was photographed in the 850–400 Å (1 Å = 10−10 m) wavelength region. Nineteen lines were interpreted as transitions between the 4d95s and 4d95p configurations. All levels of the 4d10, 4d95s, and 4d95p configurations were established. Least-squares-fitted parametric calculations and Hartree–Fock ab initio calculations support the analyses.

Elastic least-squares reverse time migration using the energy norm

Geophysics ◽  
2018 ◽  
Vol 83 (3) ◽  
pp. S237-S248 ◽  
Author(s):  
Daniel Rocha ◽  
Paul Sava
Keyword(s):  
Least Squares ◽  
Normal Incidence ◽  
Wave Mode ◽  
Energy Norm ◽  
Earth Model ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Time Migration ◽  
Mode Decomposition ◽  
High Convergence Rate

Incorporating anisotropy and elasticity into least-squares migration is an important step toward recovering accurate amplitudes in seismic imaging. An efficient way to extract reflectivity information from anisotropic elastic wavefields exploits properties of the energy norm. We derive linearized modeling and migration operators based on the energy norm to perform anisotropic least-squares reverse time migration (LSRTM) describing subsurface reflectivity and correctly predicting observed data without costly decomposition of wave modes. Imaging operators based on the energy norm have no polarity reversal at normal incidence and remove backscattering artifacts caused by sharp interfaces in the earth model, thus accelerating convergence and generating images of higher quality when compared with images produced by conventional methods. With synthetic and field data experiments, we find that our elastic LSRTM method generates high-quality images that predict the data for arbitrary anisotropy, without the complexity of wave-mode decomposition and with a high convergence rate.

Normal-Incidence Multilayer Mirrors for the 120–450 Å Wavelength Region

1990 ◽  
Vol 2 (4) ◽  
pp. 241-248
Author(s):  
S. V. Gaponov ◽  
S. A. Gusev ◽  
V. V. Dubrov ◽  
A. I. Kuzmichev ◽  
B. M. Luskin ◽  
...  
Keyword(s):  
Wavelength Region ◽  
Normal Incidence ◽  
Multilayer Mirrors
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