Nuclear half-lives for α-radioactivity of elements with 100 ? Z ? 130

Theoretical estimates for the half-lives of about 1700 isotopes of heavy elements with 100 ? Z ? 130 are tabulated using theoretical Q-values. The quantum mechanical tunneling probabilities are calculated within a WKB framework using microscopic nuclear potentials. The microscopic nucleus-nucleus potentials are obtained by folding the densities of interacting nuclei with a density-dependent M3Y effective nucleon-nucleon interaction. The α-decay half-lives calculated in this formalism using the experimental Q-values were found to be in good agreement over a wide range of experimental data spanning about 20 orders of magnitude. The theoretical Q-values used for the present calculations are extracted from three different mass estimates viz. Myers-Swiatecki, Muntian-Hofmann-Patyk-Sobiczewski, and Koura-Tachibana-Uno-Yamada.     

Calculated half-lives and kinetic energies for spontaneous emission of heavy ions from nuclei

The most probable decays by spontaneous emission of heavy ions are listed for nuclides with Z = 47−106 and total half-lives > 1 μsec. Partial half-lives, branching ratios relative to α decay, kinetic energies, and Q values are estimated by using the analytical superasymmetric fission model, a semi-empirical formula for those α-decay lifetimes which have not been measured, and the new Wapstra-Audi mass tables. Numerous “stable” nuclides with Z > 40 are found to be metastable with respect to the new decay modes. The current experimental status is briefly reviewed.     

A mass table for 50 ≤ Z ≤ 118, 130 ≤ A ≤ 311 derived from nuclear energy systematics

The atomic masses for unknown heavy nuclides with Z = 50 – 118 and A = 130 – 311 have been derived from extrapolation of experimental nuclear energy systematics. Alpha-decay-energy systematics served as the primary basis for these extrapolations, while beta-decay and two-neutron separation-energy systematics were used as secondary bases. The 1971 Atomic Mass Evaluation of Wapstra and Gove provided the experimental input. Tabulations present atomic mass defects, alpha-decay Q-values, proton and neutron separation energies, and negatron-decay energies for each species.     

Intermediate-coupling collision strengths for P−P and P−D transitions produced by electron impact on highly charged He-like ions

Intermediate-coupling collision strengths have been calculated by a Coulomb-Born-Exchange method for all fine-structure transitions between states of the 1s2p configuration and those of the 1snp and 1snd configurations with n = 3, 4, and 5 produced by electron impact on He-like ions with nuclear charge number Z in the range 8 ≤ Z ≤ 50. For each transition results are given for impact electron energies equal to 1.0, 1.2, 1.5, 1.9, 2.5, and 4.0 times threshold. Transition energies are provided for use in converting the impact electron energies to energies in rydbergs.     

Collision strengths and line strengths for all transitions among the levels of the 1s2l2l′ configurations of Li-like ions

Collision strengths and electric-dipole line strengths have been calculated for all fine-structure transitions among the levels of the 1s2l2l′ configurations in 19 Li-like ions with nuclear charge number Z in the range 6 ⩽ Z ⩽ 74. From these results the collision strengths and line strengths for transitions between energy terms and their analogs in jj coupling can also be obtained. The collision strength data cover impact-electron energies ⩽3.25Z²Ry or 44.2Z²eV. The effects of configuration mixing, parentage mixing, and intermediate coupling have been included in the calculations. The method used in calculating the collision strengths is a Coulomb-Born-Exchange method well suited for treating many members of an isoelectronic sequence simultaneously. The complete results have been given in terms of fits to simple functions of the impact-electron energy that are readily integrated over a Maxwellian distribution to obtain collision rates.     

Strengths of gamma-ray transitions between bound states of A = 21–44 nuclei

The present tables classify the strengths of about 600 γ-ray transitions between bound states according to character (electric or magnetic), multipolarity, and isospin forbiddenness. The input material (energies, J^π-values, isobaric spins, lifetimes, branching and mixing ratios) has been provided by a recent review of the A = 21–44 nuclei. The transitions listed here are restricted to those for which the J^π- and T-values of initial and final state have been determined unambiguously (on a 99.9% probability basis) and for which the error in the strength does not exceed 50%.From a comparison of mirror transitions, additional information has been obtained on isoscalar M1 and isovector E2 transitions.From the strength distributions, a set of recommended upper limits for γ-ray strengths has been derived.     

Total and differential conversion coefficients for internal electron-positron pair creation

We calculated the e⁺, e^?-pair conversion coefficient for nuclear transitions with electric multipolarities E1, E2, and E3 and magnetic multipolarities M1, M2, and M3. Transition energies between 1100 and 8000 keV were considered. The Coulomb distortion of the electron and positron was taken into account by using relativistic continuum wave functions that are solutions of the Dirac equation for the Coulomb potential. We present numerical values for the conversion coefficient for nuclear charge numbers from Z = 0 to Z = 100.     

Energy-level scheme and transition probabilities of Si-like ions

Theoretical energy levels and transition probabilities are presented for 27 low-lying levels of silicon-like ions from Z = 15 to Z = 106. The multiconfiguration Dirac-Fock technique is used to calculate energy levels and wave functions. The Breit interaction and Lamb shift contributions are calculated perturbatively as corrections to the Dirac-Fock energy. The M1 and E2 transitions between the five levels of the ground-state configuration and the E1 transitions between excited and the ground levels are presented.     

Calculated fission barriers,ground-state masses,and particle separation energies for nuclei with 76 ≤ Z ≤ 100 and 140 ≤ N ≤ 184

We calculate fission barriers and ground-state masses for 1125 nuclei with 76 ≤ Z ≤ 100 and 140 ≤ N ≤ 184. We use the macroscopic-microscopic method to calculate the energy as a function of elongation, necking, mass-asymmetric, and axially asymmetric shape coordinates. For the macroscopic model we use the droplet model with a 1973 set of parameters. The microscopic corrections are calculated by use of the modified oscillator model. The results are summarized in two tables. The first table gives, for each nucleus, the heights relative to the ground state of the saddle points and minima of the fission barriers and the corresponding values of the shape coordinates. The second table gives the ground-state mass excess, the maximum barrier height, neutron and proton separation energies, and alpha and beta Q-values.     

Excitation energies and oscillator strengths in Al-, Si-, and P-like ions

Theoretical energy levels and transition probabilities are calculated for low-lying levels of aluminum-, silicon-, and phosphorus-like ions from Z = 13 to Z = 106. The multiconfiguration Dirac-Fock technique is used to obtain energy levels and wave functions. Electron correlation effects are accounted for by including many electronic configurations in the self-consistent-field procedure. Contributions from the Breit interaction and the Lamb shift are treated as a first-order perturbation. The electric-dipole, electric-quadrupole, and magnetic-dipole transitions between levels are also calculated.     

Collision strengths and line strengths for all transitions among the levels of the 1s22s22p, 1s22s2p2, and 1s22p3 configurations of boron-like ions

Collision strengths and electric-dipole line strengths have been calculated for all fine-structure transitions among the levels of the 1s²2s²2p, 1s²2s2p², and 1s²2p³ configurations in 17 boron-like ions with nuclear charge number Z in the range 10 ⩽ Z ⩽ 74. From these results the collision strengths and line strengths for transitions between energy terms and their analogs in jj coupling can also be obtained. The collision strength data cover impact-electron energies ⩽ 3.25Z²Ry or 44.2Z²eV. The effects of configuration mixing, parentage mixing, and intermediate coupling have been included in the calculations. The method used in calculating the collision strengths is a Coulomb-Born-Exchange method well suited for treating many members of an isoelectronic sequence simultaneously. The complete results have been given in terms of fits to simple functions of the impact-electron energy that are readily integrated over a Maxwellian distribution to obtain collision rates. Some discussion is given of important differences between the present method and the more usual Coulomb-Born-Exchange method, where it is assumed that the free electron sees the screened nuclear charge (Z - N).     

Simulated Lyman-alpha and dielectronic satellite spectra,Z = 6–20

The dielectronic satellite transitions originating on the 2l2l′ and 2l3l′ doubly excited levels of the He-like ions with Z = 6–20 are tabulated in a useful format. The relative intensities of the satellite transitions are listed for the two cases of low electron density (corona equilibrium) and high electron density (Saha equilibrium). This compilation of wavelengths and relative intensities should facilitate the identification of dielectronic satellite lines in the x-ray spectra of hot plasmas. The Lyman-α and satellite intensity distributions are simulated by convolving the calculated intensities with Gaussian profiles. These calculated spectra illustrate the blending of the satellite lines and indicate the instrumental resolution necessary to resolve the satellite features in experimental data. Also included is a bibliography of published experimental spectra for the satellites of the Lyman-α line of moderate-Z ions in dense laboratory plasmas.     

Collision strengths and line strengths for fine-structure transitions between the 2la2lb configurations and the 2l′a3l′b configurations in Be-like ions

Collision strengths have been calculated for all fine-structure transitions between the levels of the 2l_a2l_b configurations and those of the 2l′_a3l′_b configurations in 17 Be-like ions with nuclear charge number Z in the range 10 ? Z ? 74 for nine impact-electron energies ? in threshold units in the range 1 ? ? ? 15. Fits of all the collision strengths to simple functions of ? that are readily integrated over a Maxwellian distribution to obtain collision rates are given. Also given are the results for transitions between energy terms. In addition, the electric-dipole radiative line strengths and the transition energies are listed. The method used is a Coulomb-Born-exchange method that is well suited for handling many members of an isoelectronic sequence simultaneously. The calculations include both configuration mixing and intermediate coupling effects.     

Superallowed 0+ → 0+ and isospin-forbidden Jπ → Jπ fermi transitions

Experimental data on Q-values, β end-point energies, half-lives, and branching ratios pertaining to superallowed 0⁺ → 0⁺ β-transitions are complied and evaluated. Out of a total of eighteen $\text{J}$t values, seven are known to better than 0.3% accuracy. The weighted average of all values, $\text{J}$t = 3088.6 ± 2.1 sec, was employed to determine the effective vector coupling constant G′_v = (1.4115 ± 0.0005) × 10^?49 erg cm³. Experimental data on β-transitions between states of same spin but different isospin are also compiled and evaluated if they yield Fermi matrix elements. Information is obtained on isospin impurities of thirty-three nuclear states as deduced from β-decay experiments. The isospin impurities are extremely small, the largest being 0.05% reported for the ⁶⁴Ga ground state. The literature survey ended in April 1975.     

Fundamental and incidental limits on the spectroscopy of single electron ions

Precision measurements of spectra from one-electron ions are principally focused on tests of QED corrections to the energy levels implied by the Dirac equation. Even though spectroscopic tests in atomic hydrogen itself and determination of the anomalous moment of the electron have reached impressive levels of refinement and demonstrate equally impressive consistency between experiment and theory, exploration of the Z?dependence of such comparisons remains of interest. Fundamentally, such “Lamb-shift” experiments are characterized by and are limited by some “$\text{Q?}\text{value”}$ determined by the magnitude of the QED shift, S, in relation to a line-width parameter, γ. Such Q?values are rather small for the traditional Δn = 0 experiments, regardless of Z. Substantial improvement in this regard is available if one studies Δn =1 transitions, but in these cases there is a substantial, though largely incidental, penalty in loss of “ leverage” in the measurement. Additionally, and also incidentally, the earliest example of such Δn = 1 experiments have suffered from various combinations of Doppler troubles and spectator electron perturbations.Only in one very recent effort has it been possible to bring both of these problems under simultaneous control thereby inviting consideration of a still more refined level at which fundamental limitations again appear dominant. One can further deal with the dominant intrinsic limitation occurring at this stage in principle but at the cost of still more refined measurement technology which appears to be practical but to lie in the future.     

Relativistic oscillator strengths in the boron isoelectronic sequence

Oscillator strengths for electric dipole transitions, between states of the ground complex of the boron isoelectronic sequence up to Z = 93, are studied by means of relativistic wave functions obtained from a central field model. A graphical representation for 45 transitions is presented and the results are analyzed by means of the relativistic Z-dependent theory of Layzer and Bahcall. In the intermediate Z-region anticrossing effects appear which cause some irregularities in the behavior of the oscillator strengths.     

Electron impact collision strengths and oscillator strengths for Ni-like Nd, Sm, Eu, Gd, Ta, and W ions

Energy levels, oscillator strengths, and electron impact collision strengths have been calculated for Ni-like ions of Nd (Z = 60), Sm (Z = 62), Eu (Z = 63), Gd (Z = 64), Ta (Z = 73), and W (Z = 74) among the 249 levels belonging to the ([Ne])3s²3p⁶3d¹⁰, 3s²3p⁶3d⁹nl, 3s²3p⁵3d¹⁰nl, 3s3p⁶3d¹⁰nl (n = 4, 5; l = 0, 1, … , n − 1) configurations. Configuration interactions among these configurations have been included in the calculations. Collision strengths have been obtained at 20 scattered electron energies (5–20,000 eV) and they have been listed at six representative energies of 100, 400, 1000, 2500, 5000, and 10,000 eV in this work. Effective collision strengths have been obtained by assuming a Maxwellian electron velocity distribution at 24 temperatures ranging from 100 to 3000 eV. Our results are compared with those available in the literature. The relative difference is within 0.3% between our calculated energy levels and the corresponding experimental values wherever available. The energy levels are expected to be be accurate within 0.6%, while oscillator strengths and collision strengths for strong transitions are probably accurate to better than 20%. The complete dataset is available electronically from http://www.astronomy.csdb.cn/EIE/.     

Internal conversion coefficients for E5 and M5 nuclear transitions, 30 ≤ Z ≤ 104

Presented here are internal conversion coefficients (ICC) for E5- and M5-multipolarities of nuclear gamma rays for 75 values of atomic number Z in the range 30 ≤ Z ≤ 104. The tables provide the missing data for E5 and M5 transitions in the Hager and Seltzer tables. These tables contain M-shell ICC, which those of Sliv and Band do not, and are calculated in a better atomic field (Hartree-Fock-Slater). The calculations are relativistic with finite nuclear size effect taken into account. K-shell ICC for 20 values of the transition energy up to 6 MeV, L-subshell ICC for 25–26 values of the transition energy up to 2 MeV, and M-subshell ICC for 18 values of the transition energy up to ≈0.2 MeV are given.     

Quantum defect values for positive atomic ions

The asymptotic quantum defects, at the ionization limit, of s, p, d, and f atomic orbitals have been calculated in the Hartree-Slater approximation for all ionization stages of all ions with atomic number Z ⩽ 50.