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Radiative transition probabilities and oscillator strengths for 164 lines arising from 5s2ns, 5s2np, 5s2nd, 5s2nf, 5s2ng and 5s5p2 configurations of Sn II have been calculated. These values were obtained in intermediate coupling (IC) and using ab initio relativistic HartreeFock (HFR) calculations. We use for the IC calculations the standard method of least square fitting of experimental energy levels by means of computer codes from Cowan. The results of calculations for radiative transition probabilities are presented and compared with the experimental result presents in the literature and with other theoretical values. These values, although in general agreement with the rare experimental data, do present some noticeable discrepancies.

The L3 subshell x-ray intensity ratios for Ta, W, Re, Au, Hg, Tl, Pb, Th and U have been measured using an Am-241 radioisotope. Radiative transition probabilities of L3 to Mi, Ni and Oi subshells were measured by using L3 x-ray intensity ratios and Li subshell fluorescence yields. For this measurement, the new equations were used in this study. The experimental results were compared with the relativistic Hartree–Slater values of Scofield.

Multiconfiguration Dirac–Fock calculations have been carried out in the Extended Optimal Level (EOL) scheme on the energies, transition probabilities and weighted absorption oscillator strengths of intercombination lines of highly ionized argon. The calculations have been carried out in intermediate coupling with empty K shell, varying degrees of ionization in the L shell and open outer shells. The radiative transition rates have been calculated in both length and velocity gauges and an analysis on the accuracy of the orbital functions used in this work has been attempted by comparing the length form and velocity form transition rates.

The atomic nuclear charge (Z) dependence of the dielectronic recombination (DR) rate coefficient (α) to the O4+, Ne6+, Mg8+, P11+, Ar14+, Ca16+, V19+, Fe22+ ions as well as the auger energy (ΔE), the radiative transition probability (Ar), and the autoionization rate (Aa) for the Be-like ions is studied both in quality and quantity. For the calculation of the energy levels, Ar and Aa values, Cowan's code is employed. As for the doubly excited states, 1s23lnl' (l = s, p, d) are considered as well as 1s22pnl states. In the DR processes, at low Z, only the 1s22pnl → 1s22snl and 1s23pnl → 1s22snl processes give a significant contribution. While, at high Z, the 1s23s(or d)nl → 1s22pnl and 1s22pnl → 1s22pn'l' processes also become important. The dielectronic recombination rate coefficient to the final excited 1s22snl show weak Z-dependence, on the other hand, those to the final excited 1s22pnl states have a strong Z-dependence.

Energy levels, radiative transition probabilities and autoionization rates for CuXIX including the 1s22s22p53lnl' (n = 3 ÷ 8, l' ≤ n – 1) and 1s22s2p63lnl' (n = 3 ÷ 4, l' ≤ n – 1) doubly excited states were calculated using the multi-configurational Hartree–Fock method (Cowan code). Contributions of relativistic effects were discussed in comparison with data obtained by the multi-configurational Dirac–Fock method (YODA code). Application of the theoretical data for interpretation of experimental spectra obtained by double-electron capture in slow ion-atom collisions is discussed.

A detailed investigation of radiative transition probabilities has been performed for the magnetic dipole (M1) and electric quadrupole (E2) transitions involving the metastable energy levels within the 3d5 and 3d44s configurations of Cr II. The pseudo relativistic Hartree-Fock (HFR) method, combined with an optimization of radial parameters based on the available observed energy levels, has been used for the calculations.

The dipole matrix element in the first order of the perturbation theory by 1/Z, Z being the nuclear charge, has been calculated for all the possible radiative transitions (nl)k(n'l')k'Φ – (nl)k+1(n'l')k' - 1Φ with the electronic configuration Φ = 1sk12sk22pk33sk43pk53dk64sk74pk84dk94fk10, nl and n'l' belonging to any subshell of this configuration. The Kα x-ray emission rates for atoms with Z = 10–36 have been calculated and compared with other theoretical results. The contribution of the first order of the dipole matrix element to the radiative transition probability has also been studied.

Energy levels, radiative transition probabilities and autionization rates for C II including 1s22l2l'nl" (n = 2–6, l" ≤ (n − 1)] states were calculated by using the multi-configurational Hartree-Fock (Cowan code) method. Autoionizing levels above three thresholds: 1s22s2(1S), 1s22s2p(3P), 1s22s2p(1P) were considered. Branching ratios relative to the first threshold and intensity factors were calculated for satellite lines and dielectronic recombination rate coefficients for C II ions.

Relative intensities of dielectronic satellite lines determined by radiative transition probabilities and autoionization rates are calculated for transitions 1s2lnl'-1s2nl', 1s2lnl'-1s22l (n = 4-10, l = 0-3) for Li-like ions with Z = 5-54 by using the perturbation theory method (Z-expansion). Relativistic effects are taken into account by the Breit-Pauli operators. It was observed that the relative factor intensity changes very sharply with n and Z due to redistribution between contributions of relativistic and correlation effects.

The M x-rays of Th and U have been produced by alpha particle bombardment in the energy range of 2.5-4.5 MeV. N6,7 → M5(Mα), N6 → M4(Mβ), N5 → M3(Mγ), N4 → M2 and N2 → M1 lines were selected to deduce M-subshell x-ray production cross sections. The radiative transition rates and the Coster-Kronig yields and M-subshell fluorescence yields were used to convert the x-ray production cross sections into M-subshell ionization cross sections. The deduced M-subshell ionization cross sections were compared with the ECPSSR predictions. The discrepancies of our experimental results from the theoretical calculations are discussed.

In the present study, various concentrations of ErF3-doped CaF2 crystals were grown using the vertical Bridgman method. The Judd–Ofelt intensity parameters Ω t (t= 2, 4, 6) for f–f transitions of Er3 + ions were determined from optical absorption spectra. The concentration dependence of the intensity parameters radiative transition probability, oscillator strength, branching ratio and radiative lifetime was also investigated. The predicted radiative lifetimes were compared with those of the Er3 + transitions reported in various hosts. Apart from the green and red emissions, reported by other researchers, a UV (314 nm) emission band was observed, not reported previously.

A detailed investigation of energy levels and radiative transition probabilities is presented for the n = 4, Δn = 0 transitions of the ions Rb VIII to Xe XXV along the zinc isoelectronic sequence. The Relativistic Hartree-Fock method is applied for the calculations combined with Slater parameter optimization procedures. Comparisons with multiconfigurational Dirac-Fock calculations show that the most important relativistic effects are taken into account.

We have calculated energy levels and radiative transition probabilities in the ground configurations of the sulfur and selenium isoelectronic sequences up to molybdenum and silver, respectively. Transition probabilities have been obtained for M1 and E2 forbidden lines within the p4 configurations using electrostatic and spin-orbit integrals for the interactions within this configuration deduced by a fitting procedure to the available experimental energy levels or by graphical inter(extra)polation of Slater parameters along the sequence when the energy levels are unknown. Some of the most important configuration interaction and relativistic effects have been included explicitly using the HFR self-consistent method due to Cowan and Griffin. For most of the ions in the selenium sequence, transition probabilities are reported for the first time. The effects of including configurations with 4f electrons explicitly have been studied for both the 3p3 and 3p4 configurations.

The concept of a "Superheavy Quasiatom" is discussed. Radiative transition times are compared with the lifetime of the intermediate system, cross sections are calculated within a two-collision model and induced transitions and their anisotropic emission are discussed. Recent experimental and theoretical results are presented from collision systems obtained with I-beams bombarding various heavy targets, giving combined Z-values between 120 and 145. Results include the energy dependence of the peak structure interpreted as M X-rays from superheavy quasiatoms and the anisotropy of X-ray emission referred to the beam direction. The data are discussed within the models available. These cannot explain the strong emission of anisotropic radiation in the X-ray energy range of quasiatomic M X-ray at small bombarding energies.

A review of recent investigations on tunable far infrared semiconductor lasers on hot holes in Ge are given. This laser operates due to inverted hot hole distributions caused by the accumulation of carriers in crossed E and B fields in special regions of the momentum space. A radiative transition responsible for the simulated emission is the transition between subbands of light and heavy holes or between light hole Landau levels. Some additional possibilities to obtain inverted distributions are discussed.

Calculated oscillator strengths are listed for 2s2 2p5 - 2s 2p6, 2s2 2p5 - 2s2 2p4ns, 2s2 2p5 - 2s2 2p4nd and for 2s2 2p4nl - 2s2 2p4n'l' (l = s, p; l' = p, d; n, n' = 3, 4) transitions of Mg IV. They have been computed with the aid of a HXR computer program, initially developed by Cowan [18], including configuration interaction and some relativistic effects. Ab initio values of Slater radial energy integrals have been adjusted by a non-linear least-square optimization routine, using the available experimental energy levels.