Experimental and theoretical radiative properties of odd-parity highly excited levels in Mo II

Abstract

Abstract. Radiative lifetimes of 13 odd-parity levels of Mo II have been measured using time-resolved laser-induced fluorescence (TR-LIF) spectroscopy in a plasma produced by laser ablation. The investigated levels, within the energy range 48 022−63 497 cm −1 , were excited from the ground or appropriate metastable states with one-photon selective excitation. The uncertainties of the measured lifetime results are less than 10%. Calculated lifetimes of Mo II, obtained using the relativistic Hartree-Fock (HFR) method including core-polarization effects, are found to agree well with the measured ones. New transition probabilities are deduced for 246 transitions in the wavelength range extending from 207.431 up to 510.813 nm.

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

“…In practice, this parameter is usually chosen to be equal to the HFR mean value < r > for the outermost ionic core orbital. When looking at Table 1 , one can observe that ab initio HFR radial dipole integrals are about 20% larger than the values extracted from our oscillator strength parametrization (OSP) approach while the difference is reduced to a few percent when considering the HFR + CPOL results obtained using a Mo IV ionic core, as reported in [10,11] . In the same Table, for further analysis, we have also added HFR and HFR + CPOL radial integral values for transitions involving the 4d 3 5s5p configuration.…”

“…Eighteen years later Sikström et al [9] reported experimental branching fraction values, ranging in the wavelength from 1970 to 4370 Å and radiative lifetime measurements for 10 levels. We have to mention also the complementary extensions on the same subject, done by Lundberg et al [10] and Jiang et al [11] . Recently a Spanish team has presented numerous new oscillator strength measurements, arising mainly from highly excited levels [12,13] .…”

“…The oscillator strengths obtained in our work with the semiempirical oscillator strength parametrization (OSP) method are compared with the available experimental values [9,12,13] in Table 3 for Mo II spectral lines in the region 20 0 0-40 0 0 Å They are also compared with the values calculated using the HFR + CPOL approach. As the physical model considered in the latter method was exactly the same as the one described in our recent study of singly ionized molybdenum [10,11] , the details will not be repeated here. Let us just remind that, in these works, the configurations 4d 5 , 4d 4 5s, 4d 4 6s, 4d 4 5d, 4d 3 5s 2 , 4d 3 5p 2 , 4d 3 5d 2 , 4d 3 5s5d (even parity) and 4d 4 5p, 4d 4 6p, 4d 4 4f, 4d 4 5f, 4d 3 5s5p, 4d 3 5p5d (odd parity) were included in the calculations with the dipole polarizability α d = 5.67 a 0 3 [20] and the cut off radius r c = 1.73 a 0 as core-polarization parameters.…”

Hyperfine structure and isotope shifts in Mo II

“…In the case of Mo II, an extensive analysis of a Fourier transform spectrum has been carried out by Nilsson and Pickering [34], who added 110 new levels to those in previous work by Kiess [35]. Measurements and calculations of lifetimes and transition probabilities have been made by Jiang et al [36], Lundberg et al [37], Sikstrom et al [38], Schnehage et al [39], and Hannaford and Lowe [40].…”

Spectral investigation of doubly ionized rubidium (Rb III) from relativistic Hartree-Fock calculations

“…The present work can be seen as an extension of our recent investigations of the fifth row elements Y II, Y III [5], a e-mail: pascal.quinet@umons.ac.be Zr II [6], Nb I [7], Nb II, Nb III [8], Mo II [9][10][11], Tc II [12], Ru I [13], Ru II, Ru III [14], Rh II [15,16], Rh III [17], Pd I [18], Pd III [17], Ag II [19,20], Ag III [17], Sn I [21][22][23], Sb I [24], Te II and Te III [25].…”