[en] Even-parity configuration system of Ti I has been considered on the basis of the experimental data available in literature. The fine structure analysis has been performed with the aid of a linked-parameter method of level-fitting calculations in a large multiconfiguration basis. Fine structure parameters have been determined and precise wavefunctions of even energy levels have been evaluated. Appropriate pseudorelativistic Hartree-Fock ab initio calculations of fine structure parameters have been presented for comparison purposes. Configuration interaction effects on even-parity configurations have been discussed. (orig.)

[en] We report a new method of level-fitting calculations (FS-fit, fine structure fit) in a large multiconfiguration basis. This method allows inclusion of all electrostatic and spin-orbit interactions predicted for the system under study. This has been achieved without accruing interaction parameters faster than level data by relating interaction parameters to the ratios determined on the basis of their effective quantum numbers. The method has been tested for the system consisting of 33 configurations of Si I and a very good FS-fit has been achieved with a mean deviation of 4 cm^-1. The method proposed should also yield eigenvectors that can be used to calculate other physical observables with a comparable precision. Moreover, we are able to predict a destructive interference effect on the line strength due to the relative phases of eigenvectors. An example of the absence of some transitions in the silicon spectrum is discussed. (orig.)

[en] In order to analyse interactions between nsnp⁴ and even configurations ns²np²n'l' (where l'=s or d), as well as to quantitatively describe the strength of interaction and the influence of the configuration nsnp⁴, with open inner ns shell, on the spectrum of these even configurations the parametrization method of the model space Σsub(n')ns²np²n's+Σsub(n⁰)ns²np²n''d+nsnp⁴ is considered. In our model, electrostatic, spin-orbit, electrostatically correlated spin-orbit interaction within each of component configuration of the system, and electrostatic interactions between these configurations are included. The interactions with distant configurations have been taken into account by including Trees terms in the energy matrix. A reduction of the number of free parameters by using the relations Rsup(k)(a,b)/Rsup(k)(c,d)=[nsup(*)(c)nsup(*)(d)/nsup(*)(a)nsup(*)(b)]sup(3/2) is proposed. The symbols a, b, c and d denote ns²np²n'l' configurations, the nsup(*)(ns²np²n'l') are the effective quantum numbers of the barycentres of the configurations ns²np²n'l' rather than those of the electronic levels. (orig.)

[en] A method of simultaneous parametrization of one- and two-body interactions on atomic hyperfine structure of configuration lsup(N) is proposed and applied for the analysis of the configuration (6p)³ in the bismuth atom. For this purpose, the hyperfine structure splittings of the levels ²Dsub(3/2)⁰, ²Dsub(5/2)⁰ and ²Psub(1/2)⁰ were measured. (orig./WL)

[en] Odd-parity configuration system of Eu I has been considered on the basis of the experimental data available in literature. The fine structure (fs) analysis has been performed with the method of level-fitting calculations in a large multiconfiguration system (4f⁷6S², 4f⁷5d⁶s, 4f⁷5d⁷s, 4f⁷6snd (n= 6,7,8,9), 4f⁷5d², 4f⁷6p², 4f⁷6sns (n=7,8,9,10), 4f⁶6s²np (n=6,7), 4f⁶5d6s6p). Fine structure parameters have been determined and wavefunctions of odd energy levels have been evaluated. On the basis of earlier hyperfine structure (hfs) experimental results, hfs analysis of the odd configuration system given above of Eu I, has been performed utilizing semi-empirical method. Configuration interaction effects for fs and hfs have been discussed

[en] Within the framework of systematic hyperfine structure (HFS) investigation of titanium atom the hfs splitting of 3d³ 4s ³H_4,5,6 levels for two stable isotopes ⁴⁷Ti and ⁴⁹Ti have been measured by laser induced fluorescence. Experimental HFS constants A_exp and B_exp have been determined. The HFS measurements confirm an existence of a significant spin-dependent interaction effect on HFS structure of the level 3d³ 4s ³H₄. (orig.)

No abstract available

No abstract available

[en] Within the framework of systematic hyperfine structure (hfs) investigation of titanium atom the hfs-splittings of 3d³(²G)4s b ¹G₄ levels for two stable isotopes ⁴⁷Ti and ⁴⁹Ti have been studied. 5 hfs intervals for each isotope have been measured using ABMR-LIRF method (atomic beam magnetic resonance detected by laser induced resonance fluorescence) with an accuracy of about 300 Hz. The J-off-diagonal second order perturbation effects have been taken into account in the interpretation. Upper limit of the contributions from octupole and hexadecapole hyperfine structure interaction to hfs intervals of this level have been estimated to be about 400 Hz. However, for most of hfs intervals these contributions are almost within experimental error and in order to study such effects a more precise experimental method should be used. (orig.)

[en] Hyperfine separations in unstable Eu⁺ ions of mass 148, 149, and 150 have been measured in laser-microwave double-resonance experiments in a Paul ion trap. In spite of the small available quantities of the isotopes, the experimental uncertainties are of the order of 10^-8 or below, which is of the same order as in earlier measurements on stable isotopes of Eu⁺. Extensive second-order perturbation calculation is required to obtain coupling constants for magnetic-dipole (A) and electric-quadrupole (B) interactions. The uncertainties are a few times 10^-7 for A and 10^-3 for B. The experiments are a step in an attempt to determine the differential hyperfine anomaly (Bohr-Weisskopf effect) in a long chain of isotopes. copyright 1997 The American Physical Society