Program to calculate pure angular momentum coefficients in jj-coupling

A program for computing pure angular momentum coefficients in relativistic atomic structure for any scalar one- and two-particle operator is presented. The program, written in Fortran 90/95 and based on techniques of second quantization, irreducible tensorial operators, quasispin and the theory of angular momentum, is intended to replace existing angular coefficient modules from GRASP92. The new module uses a different decomposition of the coefficients as sums of products of pure angular momentum coefficients, which depend only on the tensor rank of the interaction but not on its details, with effective interaction strengths of specific interactions. This saves memory and reduces the computational cost of big calculations signficantly

Electric dipole moments of superheavy elements - A case study on copernicium

The multiconfiguration Dirac-Hartree-Fock (MCDHF) method was employed to calculate atomic electric dipole moments (EDM) of the superheavy element copernicium (Cn, $Z=112$). The EDM enhancement factors of Cn, here calculated for the first time, are about one order of magnitude larger than those of Hg. The exponential dependence of enhancement factors on atomic number $Z$ along group 12 of the periodic table was derived from the EDMs of the entire homolog series, $^{69}_{30}$Zn, $^{111}_{\phantom{1}48}$Cd, $^{199}_{\phantom{1}80}$Hg, $^{285}_{112}$Cn, and $^{482}_{162}$Uhb. These results show that superheavy elements with sufficiently large half-lives are good candidates for EDM searches.Comment: 10 pages, 3 figure

Hyperfine induced 1s2s ^1S_0 \to 1s^2 ^1S_0 M1 transition of He-like ions

Hyperfine induced 1s2s ^1S_0 \to 1s^2 ^1S_0 M1 transition probabilities of He-like ions have been calculated from relativistic configuration interaction wavefunctions including the frequency independent Breit interaction and QED effects. Present results for {$^{151}$}Eu and {$^{155}$}Gd are in good agreement with previous calculations [Phys. Rev. A {\bf 63}, 054105 (2001)]. Electronic data are given in terms of a general scaling law in $Z$ that, given isotopic nuclear spin and magnetic moment, allows hyperfine induced decay rates to be estimated for any isotope. The results should be helpful for future experimental investigations on QED and parity non-conservation effects.Comment: 9 pages, 2 figure

Multiconfiguration Dirac-Hartree-Fock calculations of atomic electric dipole moments of 225^Ra, 199^Hg, and 171^Yb

The multiconfiguration Dirac-Hartree-Fock (MCDHF) method has been employed to calculate atomic electric dipole moments (EDM) of 225^Ra, 199^Hg, and 171^Yb. For the calculations of the matrix elements we extended the relativistic atomic structure package GRASP2K. The extension includes programs to evaluate matrix elements of (P, T)-odd e-N tensor-pseudotensor and pseudoscalar-scalar interactions, the atomic electric dipole interaction, the nuclear Schiff moment, and the interaction of the electron electric dipole moment with nuclear magnetic moments. The interelectronic interactions were accounted for through valence and core-valence electron correlation effects. The electron shell relaxation was included with separately optimised wave functions of opposite parities

Effects of the electron correlation and Breit and hyperfine interactions on the lifetime of the 2p5^53s states in neutral neon

In the framework of the multiconfiguration Dirac-Hartree-Fock method, we investigate the transition properties of four excited states in the $2p^53s$ configuration of neutral neon. The electron correlation effects are taken into account systematically by using the active space approach. The effect of higher-order correlation on fine structures is shown. We also study the influence of the Breit interaction and find that it reduces the oscillator strength of the $^3P^o_1 - ^1S_0$ transition by 17%. It turns out that the inclusion of the Breit interaction is essential even for such a light atomic system. Our ab initio calculated line strengths, oscillator strengths and transition rates are compared with other theoretical values and experimental measurements. Good agreement is found except for the $^3P^o_2 - ^1S_0$ M2 transition for which discrepancies of around 15% between theories and experiments remain. In addition, the impact of hyperfine interactions on the lifetimes of the $^3P^o_0$ and $^3P^o_2$ metastable states is investigated for the $^{21}$Ne isotope (I=3/2). We find that hyperfine interactions reduce the lifetimes drastically. For the $^3P^o_0$ state the lifetime is decreased by a factor of 630.Comment: Accepted by Phys. Rev.

The α-dependence of transition frequencies

Using multiconfiguration Dirac-Hartree-Fock (MCDHF) method we calculated the dependence of the transition frequencies on fine-structure constant α. The energies and relativistic energy shifts are compared with results from Dzuba et al [1], Berengut et al [2] and King et al [3]

Multiconfiguration Dirac-Hartree-Fock calculations of EDM for Ra, Hg, Yb

Using multiconfiguration Dirac-Hartree-Fock (MCDHF) method, we calculated the atomic electric dipole moment (EDM) for Ra, Hg, Yb, arising from nuclear Schiff moment, (P,T)-odd electron-nucleon interactions, and interaction of electron EDM with nuclear electromagnetic field

Calculation of reduced coefficients and matrix elements in jj-coupling

A program RCFP will be presented for calculating standard quantities in the decomposition of many-electron matrix elements in atomic structure theory. The list of quantities wich are supported by the present program includes the coefficients of fractional parentage, the reduced coefficients of fractional parentage, the reduced matrix elements of the unit operator T^{(k)} as well as the completely reduced matrix elements of the operator W^{(k_jk_q)} in jj-coupling. These quantities are now available for all subshells (nj) with j \leq 9/2 including partially filled 9/2-shells. Our program is based on a recently developed new approach on the spin-angular integration which combines second quantization and quasispin methods with the theory of angular momentum in order to obtain a more efficient evaluation of many-electron matrix elements. An underlying Fortran 90/95 module can directly be used also in (other) atomic structure codes to accelerate the computation for open-shell atoms and ions