248 research outputs found
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Relativistic many-body calculations of electric-dipole lifetimes, rates, and oscillator strengths of Delta(n) = 0 transitions between 3l^-1 4l' states in Ni-like ions
Transition rates, oscillator strengths, and line strengths are calculated for electric-dipole (E1) transitions between odd-parity 3s{sup 2}3p{sup 6}3d{sup 9}4{ell}{sub 2}, 3s{sup 2}3p{sup 5}3d{sup 10}4{ell}{sub 2}, and 3s3p{sup 6}3d{sup 10}4{ell}{sub 1} states and even-parity 3s{sup 2}3p{sup 6}3d{sup 9}4{ell}{sub 2}, 3s{sup 2}3p{sup 5}3d{sup 10}4{ell}{sub 1}, and 3s3p{sup 6}3d{sup 10}4{ell}{sub 2} (with 4{ell}{sub 1} = 4p; 4f and 4{ell}{sub 2} = 4s; 4d) in Ni-like ions with the nuclear charges ranging from Z = 34 to 100. Relativistic many-body perturbation theory (RMBPT), including the Breit interaction, is used to evaluate retarded E1 matrix elements in length and velocity forms. The calculations start from a 1s{sup 2}2s{sup 2}2p{sup 6}3s{sup 2}3p{sup 6}3d{sup 10} Dirac-Fock potential. First-order RMBPT is used to obtain intermediate coupling coefficients and second-order RMBPT is used to calculate transition matrix elements. Contributions from negative-energy states are included in the second-order E1 matrix elements to ensure the gauge independence of transition amplitudes. Transition energies used in the calculation of oscillator strengths and transition rates are from second-order RMBPT. Lifetimes of the 3s{sup 2}3p{sup 6}3d{sup 9}4d levels are given for Z = 34-100. Transition rates, line strengths, and oscillator strengths are compared with critically evaluated experimental values and with results from other recent calculations. These atomic data are important in modeling of M-shell radiation spectra of heavy ions generated in electron beam ion trap experiments and in M-shell diagnostics of plasmas
Towards a Mg lattice clock: Observation of the transition and determination of the magic wavelength
We optically excite the electronic state in Mg atoms,
laser-cooled and trapped in a magic-wavelength lattice. An applied magnetic
field enhances the coupling of the light to the otherwise strictly forbidden
transition. We determine the magic wavelength, the quadratic magnetic Zeeman
shift and the transition frequency to be 468.463(207)nm,
-206.6(2.0)MHz/T and 655 058 646 691(101)kHz, respectively. These
are compared with theoretical predictions and results from complementary
experiments. We also developed a high-precision relativistic structure model
for magnesium, give an improved theoretical value for the blackbody radiation
shift and discuss a clock based on bosonic magnesium.Comment: 5 pages, 3 figure
Relativistic coupled-cluster calculations of Ne, Ar, Kr and Xe: correlation energies and dipole polarizabilities
We have carried out a detailed and systematic study of the correlation
energies of inert gas atoms Ne, Ar, Kr and Xe using relativistic many-body
perturbation theory and relativistic coupled-cluster theory. In the
relativistic coupled-cluster calculations, we implement perturbative triples
and include these in the correlation energy calculations. We then calculate the
dipole polarizability of the ground states using perturbed coupled-cluster
theory.Comment: 10 figures, 6 tables, submitted to PR
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Relativistic many-body calculations of multipole (E1, M1, E2, M2, E3, M3) transition wavelengths and rates between 3l-14l' excited and ground states in nickel-like ions
Wavelengths, transition rates, and line strengths are calculated for the 76 possible multipole (E1, M1, E2, M2, E3, M3) transitions between the excited 3s{sup 2}3p{sup 6}3d{sup 9}4l, 3s{sup 2}3p{sup 5}3d{sup 10}4l, and 3s3p{sup 6}3d{sup 10}4l and the ground 3s{sup 2}3p{sup 6}3d{sup 10} states in Ni-like ions with the nuclear charges ranging from Z = 30 to 100. Relativistic many-body perturbation theory (RMBPT), including the Breit interaction, is used to evaluate energies and transition rates for multipole transitions in hole-particle systems. This method is based on relativistic many-body perturbation theory, agrees with MCDF calculations in lowest-order, includes all second-order correlation corrections and includes corrections from negative energy states. The calculations start from a 1s{sup 2}2s{sup 2}2p{sup 6}3s{sup 2}3p{sup 6}3d{sup 10} Dirac-Fock potential. First-order perturbation theory is used to obtain intermediate-coupling coefficients, and second-order RMBPT is used to determine the matrix elements. The contributions from negative-energy states are included in the second-order E1, M1, E2, M2, E3, and M3 matrix elements. The resulting transition energies and transition rates are compared with experimental values and with results from other recent calculations. As a result, we present wavelengths and transition rates data for the selected transitions that includes the 76 possible multipole (E1, M1, E2, M2, E3, M3) transitions between the excited 3s{sup 2}3p{sup 6}3d{sup 9}4l, 3s{sup 2}3p{sup 5}3d{sup 10}4l, and 3s3p{sup 6}3d{sup 10}4l states and the ground 3s{sup 2}3p{sup 6}3d{sup 10} state in Ni-like ions. Trends of the line strengths for the 76 multipole transitions and oscillator strengths for the 13 E1 transitions as function of Z are illustrated graphically. The Z dependence of the energy splitting for all triplet terms of the 3s{sup 2}3p{sup 6}3d{sup 9}4l, 3s{sup 2}3p{sup 5}3d{sup 10}4l, and 3s3p{sup 6}3d{sup 10}4l configurations are shown in the range of Z = 30-100
High-precision calculations of In I and Sn II atomic properties
We use all-order relativistic many-body perturbation theory to study 5s^2 nl
configurations of In I and Sn II. Energies, E1-amplitudes, and hyperfine
constants are calculated using all-order method, which accounts for single and
double excitations of the Dirac-Fock wave functions.Comment: 10 pages, accepted to PRA; v2: Introduction changed, references adde
Electric dipole moment enhancement factor of thallium
The goal of this work is to resolve the present controversy in the value of
the EDM enhancement factor of Tl. We have carried out several calculations by
different high-precision methods, studied previously omitted corrections, as
well as tested our methodology on other parity conserving quantities. We find
the EDM enhancement factor of Tl to be equal to -573(20). This value is 20%
larger than the recently published result of Nataraj et al. [Phys. Rev. Lett.
106, 200403 (2011)], but agrees very well with several earlier results.Comment: 5 pages; v2: link to supplemental material adde
Energy levels and lifetimes of Nd IV, Pm IV, Sm IV, and Eu IV
To address the shortage of experimental data for electron spectra of
triply-ionized rare earth elements we have calculated energy levels and
lifetimes of 4f{n+1} and 4f{n}5d configurations of Nd IV (n=2), Pm IV (n=3), Sm
IV (n=4), and Eu IV (n=5) using Hartree-Fock and configuration interaction
methods. To control the accuracy of our calculations we also performed similar
calculations for Pr III, Nd III and Sm III, for which experimental data are
available. The results are important, in particular, for physics of magnetic
garnets.Comment: 4 pages 1 tabl
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