Hyperfine structure, lifetime and oscillator strength of V II

Journal of Quantitative Spectroscopy and Radiative Transfer

2017

We present a semi-empirical determination of Mo II radiative parameters in a wide wavelength range 1716-8789 Å . Our fitting procedure to experimental oscillator strengths available in the literature permits us to provide reliable values for a large number of Mo II lines, predicting previously unmeasured oscillator strengths of lines involving 4d 4 5p and 4d 3 5s5p odd-parity configurations. The extracted transition radial integral values are compared with ab-initio calculations: on average they are 0.88 times the values obtained with the basic pseudo-relativistic Hartree Fock method and they agree well when core polarization effects are included. When making a survey of our present and previous studies and including also those given in the literature we observe as general trends a decreasing of transition radial integral values with filling nd shells of the same principal quantum numbers for n d k ( n + 1)s → n d k ( n + 1)p transitions.

Section: Oscillator Strength Calculationmentioning

confidence: 99%

Semi-empirical calculations of radiative decay rates in Mo II. A comparison between oscillator strength parametrization and core-polarization-corrected relativistic Hartree-Fock approaches

Journal of Quantitative Spectroscopy and Radiative Transfer

2017

“…Finally our investigation of singly ionized hafnium was extended by comparing our calculated oscillator strengths with available experimental data and by predicting new values for a rather large number of transitions. We hope that this work, in the image of our previous studies [16][17][18][19][20][21][22][23][24], will constitute a good stimulus and a useful guide for experimenters to perform further spectroscopic measurements in this ion.…”

Section: Resultsmentioning

confidence: 85%

Semi-empirical studies of atomic transition probabilities, oscillator strengths and radiative lifetimes in Hf II

Journal of Quantitative Spectroscopy and Radiative Transfer

2015

Self Cite

a b s t r a c tOver the past few years, laser induced fluorescence and Fourier Transform techniques have been applied to measure radiative lifetimes and branching fractions in Hf II in order to derive oscillator strengths and transition probabilities. In the present work, we propose to compare for the first time these experimental data to computed values obtained by two different semi-empirical approaches, respectively based on a parametrization of the oscillator strengths and on a pseudo-relativistic Hartree-Fock model including corepolarization effects. The overall agreement between all sets of data is found to be good. We furthermore give radial integrals of the main atomic transitions in this study: 〈5d6s6p| r 1 |5d 2 6s〉¼ 0.1504 (0.0064), 〈6s 2 6p|r 1 |5d6s 2 〉¼ 1.299 (0.012), 〈5d 2 6p|r 1 |5d 2 6s〉¼ À0.298 (0.013), 〈5d 2 6p|r 1 |5d 3 〉¼ 2.025 (0.027). Finally a new set of oscillator strengths and transition probabilities is reported for many transitions in Hf II.

“…Nevertheless we have to point out that 3d 4 5s levels were correctly assigned in previous studies and we have not changed any label of these levels. To compute oscillator strength values we used two different approaches, namely the HFR+CPOL model [9,10] and oscillator strength parameterization (OSP) method [11,12]. For the latter we need experimental data since transition radial integrals are treated as free parameters in the least squares fit to experimental gf values.…”

Section: Introductionmentioning

confidence: 99%

Second spectrum of chromium (Cr II), Part III: Radiative lifetimes and transition probabilities from highly excited 3d45s levels

Atomic Data and Nuclear Data Tables

2018

In this study we have extended our previous investigations of Cr II spectrum to levels of the 3d 4 5s configuration. Once again an overall good agreement is observed for these levels between experimental oscillator strength values and our calculated data using two different approaches, namely the oscillator strength parameterization and the HFR+CPOL methods. Recurring to the latter model we have computed radiative lifetime values for 20 3d 4 5s levels, confirming the well founded basis of recent experimental data, given in literature. From the use of the former method and with the help of a least squares fitting procedure to available experimental gf-values we have taken advantage of extracting for the first time the transition radial integral value for 3d 4 4p−3d 4 5s, ⟨4p|r 1 |5s⟩ = 1.962±0.005, which is confirmed favorably by ab initio results, obtained by the HFR method scaled by a factor 0.92 or directly by the HFR+CPOL approach. Finally a long list of semi-empirical oscillator strength, transition probability and branching fraction values is generated for around 500 Cr II transitions depopulating the 3d 4 5s levels. Our new gf data are compared successfully with those given by Kurucz.