Relativistic multiconfiguration calculations of the 2s22p 2P3/2 level lifetime along the boron isoelectronic sequence (original) (raw)
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Atomic Data and Nuclear Data Tables, 2008
A relativistic multi-configuration Dirac-Fock technique has been used for computing the transition wavelengths, transition probabilities, absorption oscillator strengths, and line strengths for the Ka and Kb line transitions of He-like to Ne-like molybdenum ions. The contributions from the Breit interaction, quantum electrodynamic corrections, and nuclear mass corrections to the initial and final levels have been taken into account. Transitions from the ground state to the n = 2 and 3 states of He-like and Li-like molybdenum have been calculated using two sets of configuration-interaction wavefunctions. One set of wavefunctions was generated using the fully relativistic GRASPVU code and the other was obtained using GRASP 2 , the calculated transition wavelength, transition probabilities, and absorption strengths obtained by these two independent methods are in very good agreement and there is good agreement between these results and recent theoretical and experimental results. These data provide reference values for the level lifetimes, charge state distributions, and average charge of molybdenum plasmas.
Atomistic Insights into the Irradiation Effects in Molybdenum
International Journal of Engineering Works, 2022
In this study, we examined the impact of energies of 2.54 keV and 5 keV displacement cascades in molybdenum (Mo) using an atomistic simulation at 300 K. The simulation was carried out using machines learning developed spectral neighbor analysis potential (SNAP). We computed displacement threshold energy (), vacancy formation energy () , interstitial formation energy (), interstitial cluster formation energy (), activation energy barrier of interstitial () , activation energy barrier of vacancy (), elastic properties, i.e., shear, bulk, young's modulus, poison ratio. The simulations for primary displacement cascades were performed over a statistical average of 20 independent molecular dynamics simulations such that peak time and the surviving number of defects are inversely proportional to the incident energy of primary knock-on atoms (EPKA). Additionally, it is established that the number of clusters (Nclusters) during displacement cascades is directly proportional to EPKA. Furthermore, it was revealed that the number of interstitial clusters is higher than the number of vacancy clusters. This research will provide atomic insight into the interactions of defects in Mo for the development of structural materials for high temperature applications.
High-resolution x-ray spectra from molybdenum ions in the Alcator-C tokamak
We report on measurements of the x-ray line emission in the wavelength region 0 A, =4.3 -5.3 A from molybdenum in charge states between 28+ and 32+. The experimental results were compared with calculated line spectra (also presented) which facilitated the identification of many of the principal 2p-3d, 2s-3p, and 2p-3s transitions. Some indications of weaker satellite-line contributions were also found. The principal 2p-3d transitions were found to be the dominant ones. In particular, Mo' + gave stronger contributions than other charge states for our plasma condition of T, =1.0 -1.5 keV while available calculations of relative ion abundances have predicted Mo' + to be relatively strongest at T, =2.5 -3.0 keV.
Ab initio calculations of oscillator strengths and lifetimes of low-lying states in Mo VI
2010
Relativistic coupled-cluster (RCC) calculations have been performed to estimate the electromagnetic forbidden transition probabilities, oscillator strengths and lifetimes of many low-lying states of five times ionized molybdenum (Mo VI). Contributions from the Breit interaction up to the first order of perturbation have been examined. Our results are in good agreement with the available other reported theoretical and experimental results. A long lifetime about 4.9854 s of the first excited state, 4d 2D5/2^2D_{5/2}2D5/2, has been predicted which can be a very useful criteria in the doping process of thin films. Correlations trends from various RCC terms to the transition amplitude calculations are discussed.
Multi-Configuration Dirac–Hartree–Fock (MCDHF) Calculations for B-Like Ions
Atoms, 2016
Relativistic configuration interaction results are presented for several B-like ions (Ge XXVIII, Rb XXXIII, Sr XXXIV, Ru XL, Sn XLVI, and Ba LII) using the multi-configuration Dirac-Hartree-Fock (MCDHF) method. The calculations are carried out in the active space approximation with the inclusion of the Breit interaction, the finite nuclear size effect, and quantum electrodynamic corrections. Results for fine structure energy levels for 1s 2 2s 2 2p and 2s2p 2 configurations relative to the ground state are reported. The transition wavelengths, transition probabilities, line strengths, and absorption oscillator strengths for 2s 2 2p-2s2p 2 electric dipole (E1) transitions are calculated. Both valence and core-valence correlation effects were accounted for through single-double multireference (SD-MR) expansions to increasing sets of active orbitals. Comparisons are made with the available data and good agreement is achieved. The values calculated using core-valence correlation are found to be very close to other theoretical and experimental values. The behavior of oscillator strengths as a function of nuclear charge is studied. We believe that our results can guide experimentalists in identifying the fine-structure levels in their future work.
SHAPE EVOLUTION IN HEAVIEST STABLE EVEN-EVEN MOLYBDENUM ISOTOPES STUDIED VIA COULOMB EXCITATION
2011
The quadrupole shape evolution in heaviest stable Mo isotopes is studied in terms of the shape coexistence phenomenon occurrence in this region of nuclear chart. Quadrupole deformation parameters of the 96,98,100 Mo isotopes in the low-lying (ground and excited) 0 + states were deduced using Coulomb excitation method. In all cases rich sets of electromagnetic reduced matrix elements were determined using the GOSIA code and then analysed using the Quadrupole Sum Rules formalism. Discussion of the experimental results in comparison with the predictions of microscopic calculations within the general quadrupole collective Bohr Hamiltonian model is presented for 100 Mo. 443 Int. J. Mod. Phys. E 2011.20:443-450. Downloaded from www.worldscientific.com by UNIVERSITY OF WARSAW INSTITUTE OF THEORETICAL PHYSICS -LIBRARY on 08/23/12. For personal use only. 444 K. Wrzosek-Lipska et al.
The European Physical Journal D, 1999
Spectra and decay curves of boron-like (Na VII) and beryllium-like (Na VIII) sodium ions produced by beam-foil excitation have been recorded in the 30-60 nm spectral range and the radiative lifetimes of seven n = 2 levels have been measured. The experimental results are compared with the available theoretical values and with new results obtained in the framework of two theoretical approaches: the Relativistic Hartree-Fock approximation and the Multiconfiguration Dirac-Fock method. Corroborated by the fair agreement of the new theory data with experiment, a new set of accurate transition probabilities for the 2s 2 2p-2s2p 2 and 2s2p 2-2p 3 transitions of Na VII is presented.
Electron impact ionization of hydrogen-like molybdenum ions
Journal of Physics B: Atomic, Molecular and Optical Physics, 2002
The electron impact ionization cross sections of hydrogen-like molybdenum ions were measured with an electron beam ion trap at the electron energies of 49.4, 64.4 and 79.6 keV. The results are 2.82(22) × 10 −23 , 3.13(29) × 10 −23 and 3.23(51) × 10 −23 cm 2 , respectively. These results are compared with the experimental results measured previously. The agreement with the results obtained with scaling formulae is also discussed.