Determination of transition probabilities for singly ionized vanadium

Transition probabilities of 211 spectral lines of VII, in the wavelength range 2340–4200 Å, have been determined by emission spectroscopy using a wall-stabilized arc as source. The lines studied belong to the transition arrays 3d⁴, 3d³4s-3d³4p (199 lines) and 3d³4p-3d³4d, 3d³5s (12 lines). Vanadium was introduced into the helium-arc discharge as the liquid VOCl₃. An important feature of this work is the determination of transition probabilities for many lines from a wide spectral range with a uniform absolute scale. The absolute A_ki values were obtained by normalizing relative A_ki values to an absolute scale set by ionic lifetime for the level y³H⁰₄. These results are compared with other experimental as well as theoretical results.     

Electric quadrupole transition probabilities for singly ionized magnesium

Electric quadrupole transition probabilities for Mg II have been calculated within the weakest bound electron potential model (WBEPM) theory using experimental energy levels and theoretical expectation values of orbital radii corresponding to those energy levels under the assumption of the LS coupling scheme. In this work, the WBEPM theory has been applied to forbidden transitions for the first time. The present results are consistent with earlier theoretical calculations. Some of these results are reported for the first time.     

Stark widths and transition probabilities of some multiplets of singly ionized carbon

Photoelectric measurements of lines emitted by a helium-carbon d.c. arc plasma of n_e = 1.9 × 10¹⁶cm^-3 at T = 12,800 K have been performed. Stark widths of 6 C(II) lines and transition probabilities for components of 3 C(II) multiplets were determined and compared with other experimental and theoretical data. Good agreement was generally observed except for the C(II) multiplets UV13 and UV14, where the results of Kusch deviate notably from others.     

Relativistic energies and transition probabilities for some highly excited levels in singly ionized indium

For some excited levels (n?8), the energies, wavelengths, oscillator strengths and transition probabilities calculations in singly ionized indium have been calculated within the framework of multiconfiguration Hartree-Fock approximation with relativistic corrections (Breit-Pauli Hamiltonian). The wavefunctions and some relativistic corrections have been obtained using MCHF-BP atomic package. Comparisons with other calculations and experiments are presented.     

类钠铁离子的辐射跃迁几率

本文在多组态Dirac-Fock理论框架下计算了类钠铁离子的能级及各能级n_il_i-n_kl_k,(n_i≤5,n_k≤15)间的电偶极辐射跃迁几率,证实了我们发现的新规律:在一个里德伯线系内,当上能级主量子数足够大之后,其跃迁几率仅与主量子数(不是等效主量子数)的三次方成反比。     

Transition probabilities, oscillator strengths and lifetimes for singly ionized magnesium

The electric dipole transition probabilities, oscillator strengths and lifetimes have been calculated using the weakest bound electron potential model theory (WBEPMT) for singly ionized magnesium. In the calculations both multiplet and fine structure transitions are studied. We have employed both the numerical Coulomb approximation (NCA) method and numerical non-relativistic Hartree-Fock (NRHF) wave functions for expectation values of radii. The calculated oscillator strengths and lifetimes have been compared with MCHF results given by Fischer et al. (2006). A good agreement has been obtained with the MCHF results. Moreover, some new transition probabilities, oscillator strengths and lifetime values, not existing in the data bases for highly excited levels in singly ionized magnesium, have been obtained using this method.     

The Hartree-Fock method with orthogonality restrictions for doubly excited and ionized states

It is shown that the doubly excited and ionized states with vacancies in the K electronic shells can be considered within the framework of the same scheme on the basis of the asymptotic projection method proposed earlier. In contrast to the conventional methods, the electron detachment effect is achieved by imposing the requirement that the orbitals of the excited (hole) state be orthogonal to the orbitals of removed electrons. The solution of equations that determine the orbitals is implemented in terms of the conventional spin-unrestricted Hartree-Fock method with additional conditions that ensure the spin purity and provide a unique choice of the zero-order approximation in constructing the many-particle perturbation theory for taking into account the correlation effects. The performance of the method is demonstrated by calculating the excitation energies and ionization potentials corresponding to the removal of electrons from the inner K-shell.     

Radiative lifetimes of some energy levels of doubly ionized Xenon

Using 1–5 MeV Xenon ions we have studied the beam-foil spectrum of Xenon between 105 nm and 500 nm. Radiative lifetimes were measured for levels of Xenon III. For those lifetimes which have been measured previously (Andersen et al. [l]) good agreement is obtained. The interpretation of the decay curves and the assignment of a measured value, were done with the help of theoretical lifetimes obtained by Coulomb-approximation calculations [2].     

Some new transition probabilities for mercury I

Detailed studies of a pure mercury positive column have allowed us to determine the densities and effective temperatures which characterize the discharge. From this knowledge of the discharge conditions, a series of transition probabilities is derived for 70 lines in the neutral mercury spectrum in the wavelength range 238–1530 nm, including many lines for which transition probabilities have not previously been published.     

The calculation of transition probabilities for atomic oxygen

In this contribution we present scanning tunnelling microscopy (STM) and spectroscopy (STS) investigations on isolated cobalt clusters in contact with Ge(001). Mass-filtered nanoparticles with diameters ranging from 3 to 11 nm are generated using an arc cluster ion source (ACIS) and deposited under soft landing conditions (E_kin/atom < 0.5 eV). Since the tip radius is of the same order as the nanoparticle diameters the recorded STM images are significantly affected by tip folding. By means of the “blind reconstruction method" it is possible to approximate the tip shape. After a respective deconvolution of the image structural features of the particle facets become observable. According to the equilibrium shape of the clusters being a truncated octahedron in the size range under investigation, hexagonal and rectangular features appear in the images. STS is sensitive to occupied and unoccupied states near the Fermi level and reveals the existence of distinct states in the tunnelling conductivity of the substrate as well as on the clusters. The richly structured density of states of the germanium surface serves here as tip condition test. First measurements of the tunnelling conductivity of the Co_N/Ge(001) are presented and discussed.     

Mielnik and cantoni transition probabilities

It is shown that when a Mielnik transition probability space is given, Cantoni transition probabilities can also be defined on it. A condition is given under which these transition probabilities are equal.     

Effective charges for radiative and Auger transition probabilities

Analyses of higher-order resonant, atomic collision processes require many accurate radiative and Auger transition probabilities, A_r and A_a. Numerical evaluation of these probabilities for high Rydberg states and for large angular momenta is difficult. We develop here Coulombic expressions for A_r and A_a, with effective charges for the individual orbitals involved. Simple formulas for the effective charge are proposed and tested against the more accurate data obtained with Hartree—Fock wave functions.     

Selection rules for optical transition probabilities in superlattices

Based on numerical evaluations of the transition probabilities, and using true superlattice eigenfunctions derived from the theory of finite periodic systems, new superlattice selection rules are obtained. We show that the evaluation of the large number N   of the possible recombination transitions reduces by a factor of two. We also show that taking into account these selection rules, the theoretical calculations for specific blue emitting GaN?(In_xGa_1-xN?In_yGa_1-yN)ⁿ?GaN$\text{GaN}?({\text{In}}_x{\text{Ga}}_{1-x}\text{N}?{\text{In}}_y{\text{Ga}}_{1-y}\text{N}{)}^n?\text{GaN}$ superlattices agree with those reported by Nakamura et al. [1].     

Theoretical transition probabilities for the OH meinel system

An electric dipole moment function (EDMF) for the X²Π ground state of OH based on the complete-active-space self-consistent-field plus multi-reference-singles-plus-double-excitation configuration-interaction procedure using an extended Slater basis is reported. This EDMF and the recently published MCSCF(7)-self-consistent electron pairs (SCEP) EDMF of H-J. Werner, P. Rosmus, and E-A. Reinsch [J. Chem. Phys. 79, 905–916 (1983)] (WRR) are critically compared with the “experimentally” derived EDMF. Einstein coefficients calculated with both theoretical EDMFs are substantially different than those reported by F. H. Mies [J. Mol. Spectrosc. 53, 150–188 (1974)] based on the EDMF of W. J. Stevens, G. Das, A. C. Wahl, D. Neumann, and M. Krauss [J. Chem. Phys. 61, 3686–3699 (1974)]. By shifting the WRR EDMF by 0.03 Bohr to larger r, it is possible to reproduce the accurate experimental value for the difference in dipole moments between the v = 0 and v = 1 levels measured using the molecular beam electric resonance technique. Following the theory of Mies (except that Hill and Van Vleck's intermediate coupling approximation is used), revised Einstein coefficients are tabulated for Δv = v′ – v″ ranging from the fundamental transition, Δv = 1 to the Δv = 5 overtone for v′ = 1–9, and J′ = 0.5–15.5 using the “shifted” WRR EDMF. Theoretical emission spectra are also presented, and the potential for OH involvement in the surface glow of space vehicles is briefly discussed.     

A critical survey of atomic transition probabilities for CuI

A critical survey of experimentally-determined atomic transition probabilities for 102 spectral lines of CuI has been carried out. Many of the values have been brought up to date and renormalized on the basis of recent measurements.     

Relativistic computation of intercombinational transition probabilities

Expressions have been obtained on the basis of S-matrix theory for the computation of electrical multipole transition probabilities in a relativistic approximation in a multielectron atom in first-order field perturbation theory. Also considered are corrections corresponding to simultaneously taking account of the external field and the interelectron interactions. Results of computing the wavelengths and probabilities of intercombinational transitions in multicharge ions between the configurations 1s 2p-1s² for 4 ≤ Z ≤28 and 1s² \(2s^n 1 2p^{n_2 } - 1s^2 2s^{n_1 \pm 1} 2 p^{n_2 \pm 1} \) for20 ≤ Z ≤ 30 are presented. The data obtained can be used to interpret soft x radiation originating in transitions observed in the solar corona and high-temperature plasma laboratories.