183 research outputs found
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
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 {}Eu and {}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 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
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, ). 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 along
group 12 of the periodic table was derived from the EDMs of the entire homolog
series, Zn, Cd, Hg,
Cn, and Uhb. These results show that superheavy
elements with sufficiently large half-lives are good candidates for EDM
searches.Comment: 10 pages, 3 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 2p3s 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
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 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 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 and metastable states is investigated for
the Ne isotope (I=3/2). We find that hyperfine interactions reduce the
lifetimes drastically. For the 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
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