Reactivity of Ts and At oxides and oxyhydrides with a gold surface from periodic DFT calculations.

Adsorption energies, , of oxides and oxyhydrides of the superheavy element (SHEs) Ts and of its lighter homologue At on the gold surface are predicted on the basis of relativistic periodic density functional theory calculations AMS BAND software. The following compounds were considered: MO, MO, MOO, and MO(OH) (where M = At and Ts). The aim of this study is to support "one-atom-at-a-time" gas-phase chromatography experiments on reactivity/volatility of SHEs.

A theoretical study of the adsorption behavior of superheavy 7p-elements and their compounds on a surface of gold in comparison with their lighter homologs.

Adsorption energies, , of the 7th row superheavy elements (SHEs) Lv through Og, as well as of the homologous species of the 6th row elements Po through Rn on a gold surface are predicted on the basis of relativistic periodic density functional theory calculations SCM BAND software. Since some of the elements can also form compounds such as hydrides and oxyhydrides under experimental conditions, the values of the MH (M = Bi/Mc, Po/Lv, At/Ts and Rn/Og) and MOH (M = At/Ts and Rn/Og) molecules on a gold surface were also calculated. The aim of this study is to support "one-atom-at-a-time" gas-phase chromatography experiments on the reactivity/volatility of SHEs.

Relativistic Coupled-Cluster Calculations of Spectroscopic Properties of Copernicium and Flerovium Monoxides.

Calculations of spectroscopic properties of the CnO and FlO molecules are performed using ab initio all-electron 4c- and 2c-relativistic coupled-cluster approaches with single, double, and perturbative triple excitations. The corresponding calculation for HgO is also accomplished for comparison with the published data. The dependence of the results on the parameters of the basis set and approximations used is investigated in detail.

Ground-State g Factor of Highly Charged ^{229}Th Ions: An Access to the M1 Transition Probability between the Isomeric and Ground Nuclear States.

A method is proposed to determine the M1 nuclear transition amplitude and hence the lifetime of the "nuclear clock transition" between the low-lying (∼8  eV) first isomeric state and the ground state of ^{229}Th from a measurement of the ground-state g factor of few-electron ^{229}Th ions. As a tool, the effect of nuclear hyperfine mixing in highly charged ^{229}Th ions such as ^{229}Th^{89+} or ^{229}Th^{87+} is used. The ground-state-only g-factor measurement would also provide first experimental evidence of nuclear hyperfine mixing in atomic ions.

Ab initio Calculations of Energy Levels in Be-Like Xenon: Strong Interference between Electron-Correlation and QED Effects.

The strong mixing of close levels with two valence electrons in Be-like xenon greatly complicates ab initio QED calculations beyond the first-order approximation. Because of a strong interplay between the electron-electron correlation and QED effects, the standard single-level perturbative QED approach may fail, even if it takes into account the second-order screened QED diagrams. In the present Letter, the corresponding obstacles are overcome by working out the QED perturbation theory for quasidegenerate states.

g Factor of Lithiumlike Silicon: New Challenge to Bound-State QED.

The recently established agreement between experiment and theory for the g factors of lithiumlike silicon and calcium ions manifests the most stringent test of the many-electron bound-state quantum electrodynamics (QED) effects in the presence of a magnetic field. In this Letter, we present a significant simultaneous improvement of both theoretical g_{th}=2.000 889 894 4 (34) and experimental g_{exp}=2.

How to Observe the Vacuum Decay in Low-Energy Heavy-Ion Collisions.

In slow collisions of two bare nuclei with the total charge larger than the critical value Z_{cr}≈173, the initially neutral vacuum can spontaneously decay into the charged vacuum and two positrons. The detection of the spontaneous emission of positrons would be direct evidence of this fundamental phenomenon. However, the spontaneously produced particles are indistinguishable from the dynamical background in the positron spectra.

Ab initio QED Treatment of the Two-Photon Annihilation of Positrons with Bound Electrons.

The process of a positron-bound-electron annihilation with simultaneous emission of two photons is investigated theoretically. A fully relativistic formalism based on an ab initio QED description of the process is worked out. The developed approach is applied to evaluate the annihilation of a positron with K-shell electrons of a silver atom, for which a strong contradiction between theory and experiment was previously stated.

New Nuclear Magnetic Moment of ^{209}Bi: Resolving the Bismuth Hyperfine Puzzle.

A recent measurement of the hyperfine splitting in the ground state of Li-like ^{208}Bi^{80+} has established a "hyperfine puzzle"-the experimental result exhibits a 7σ deviation from the theoretical prediction [J. Ullmann et al., Nat.

Recoil Effect on the g Factor of Li-Like Ions.

The nuclear recoil effect on the g factor of Li-like ions is evaluated. The one-electron recoil contribution is treated within the framework of the rigorous QED approach to the first order in the electron-to-nucleus mass ratio m/M and to all orders in the parameter αZ. These calculations are performed in a range Z=3-92.

Quantum Electrodynamical Shifts in Multivalent Heavy Ions.

The quantum electrodynamics (QED) corrections are directly incorporated into the most accurate treatment of the correlation corrections for ions with complex electronic structure of interest to metrology and tests of fundamental physics. We compared the performance of four different QED potentials for various systems to access the accuracy of QED calculations and to make a prediction of highly charged ion properties urgently needed for planning future experiments. We find that all four potentials give consistent and reliable results for ions of interest.

Isotope dependence of the Zeeman effect in lithium-like calcium.

The magnetic moment μ of a bound electron, generally expressed by the g-factor μ=-g μB s ħ(-1) with μB the Bohr magneton and s the electron's spin, can be calculated by bound-state quantum electrodynamics (BS-QED) to very high precision. The recent ultra-precise experiment on hydrogen-like silicon determined this value to eleven significant digits, and thus allowed to rigorously probe the validity of BS-QED. Yet, the investigation of one of the most interesting contribution to the g-factor, the relativistic interaction between electron and nucleus, is limited by our knowledge of BS-QED effects.

Nuclear Recoil Effect in the Lamb Shift of Light Hydrogenlike Atoms.

We report high-precision calculations of the nuclear recoil effect to the Lamb shift of hydrogenlike atoms to the first order in the electron-nucleus mass ratio and to all orders in the nuclear binding strength parameter Zα. The results are in excellent agreement with the known terms of the Zα expansion and allow an accurate identification of the nonperturbative higher-order remainder. For hydrogen, the higher-order remainder was found to be much larger than anticipated.

[Lead uptake by plants inoculated with plant growth-promoting rhizobacteria in heavy metal-contaminated soil].

The effects of plant growth-promoting rhizobacteria of the genus Pseudomonas on the growth and elemental composition of barley plants were examined in pot experiments under artificial contamination of soil with water-soluble Pb compounds. Bacterial inoculation reduced Pb uptake by plants at the beginning and in the first half of the growing season due to the binding of the heavy metal in organic compounds and stable complexes in the rhizosphere soil without changes in the soil medium reaction. The bacterium P.

Observation of coherence in the time-reversed relativistic photoelectric effect.

The photoelectric effect has been studied in the regime of hard x rays and strong Coulomb fields via its time-reversed process of radiative recombination (RR). In the experiment, the relativistic electrons recombined into the 2p_{3/2} excited state of hydrogenlike uranium ions, and both the RR x rays and the subsequently emitted characteristic x rays were detected in coincidence. This allowed us to observe the coherence between the magnetic substates in a highly charged ion and to identify the contribution of the spin-orbit interaction to the RR process.

Many-electron QED corrections to the g factor of lithiumlike ions.

A rigorous QED evaluation of the two-photon exchange corrections to the g factor of lithiumlike ions is presented. The screened self-energy corrections are calculated for the intermediate-Z region, and its accuracy for the high-Z region is essentially improved in comparison with that of previous calculations. As a result, the theoretical accuracy of the g factor of lithiumlike ions is significantly increased.

g Factor of lithiumlike silicon 28Si11+.

The g factor of lithiumlike silicon (28)Si(11+) has been measured in a triple-Penning trap with a relative uncertainty of 1.1×10(-9) to be g(exp)=2.000 889 889 9(21).

Test of many-electron QED effects in the hyperfine splitting of heavy high-Z ions.

A rigorous evaluation of the two-photon exchange corrections to the hyperfine structure in lithiumlike heavy ions is presented. As a result, the theoretical accuracy of the specific difference between the hyperfine splitting values of H- and Li-like Bi ions is significantly improved. This opens a possibility for the stringent test of the many-electron QED effects on a few percent level in the strongest electromagnetic field presently available in experiments.

Octupolar-excitation Penning-trap mass spectrometry for Q-value measurement of double-electron capture in (164)Er.

The theory of octupolar-excitation ion-cyclotron-resonance mass spectrometry is presented which predicts an increase of up to several orders of magnitude in resolving power under certain conditions. The new method has been applied for a direct Penning-trap mass-ratio determination of the (164)Er-(164)Dy mass doublet. (164)Er is a candidate for the search for neutrinoless double-electron capture.

Resonant enhancement of neutrinoless double-electron capture in 152Gd.

In the search for the nuclide with the largest probability for neutrinoless double-electron capture, we have determined the Q(ϵϵ) value between the ground states of (152)Gd and (152)Sm by Penning-trap mass-ratio measurements. The new Q(ϵϵ) value of 55.70(18) keV results in a half-life of 10(26)  yr for a 1 eV neutrino mass.

Screened QED corrections in lithiumlike heavy ions in the presence of magnetic fields.

A rigorous evaluation of the complete gauge-invariant set of the screened one-loop QED corrections to the hyperfine structure and g factor in lithiumlike heavy ions is presented. The calculations are performed in both Feynman and Coulomb gauges for the virtual photon mediating the interelectronic interaction. As a result, the most accurate theoretical predictions for the specific difference between the hyperfine splitting values of H- and Li-like Bi ions as well as for the g factor of the Li-like Pb ion are obtained.

Isotope shift in the dielectronic recombination of three-electron ANd57+.

Isotope shifts in dielectronic recombination spectra were studied for Li-like (A)Nd(57+) ions with A=142 and A=150. From the displacement of resonance positions energy shifts deltaE(142 150)(2s-2p(1/2))=40.2(3)(6) meV [(stat)(sys)] and deltaE(142 150)(2s-2p(3/2))=42.

Nonperturbative calculation of the two-loop lamb shift in Li-like ions.

A calculation valid to all orders in the nuclear-strength parameter is presented for the two-loop Lamb shift, notably for the two-loop self-energy correction, to the 2p-2s transition energies in heavy Li-like ions. The calculation removes the largest theoretical uncertainty for these transitions and yields the first experimental identification of two-loop QED effects in the region of the strong binding field.

Exploring relativistic many-body recoil effects in highly charged ions.

The relativistic recoil effect has been the object of experimental investigations using highly charged ions at the Heidelberg electron beam ion trap. Its scaling with the nuclear charge Z boosts its contribution to a measurable level in the magnetic-dipole (M1) transitions of B- and Be-like Ar ions. The isotope shifts of 36Ar versus 40Ar have been detected with sub-ppm accuracy, and the recoil effect contribution was extracted from the 1s(2)2s(2)2p 2P(1/2) - 2P(3/2) transition in Ar13+ and the 1s(2)2s2p 3P1-3P2 transition in Ar14+.

g-Factor of heavy ions: a new access to the fine structure constant.

A possibility for a determination of the fine structure constant in experiments on the bound-electron g-factor is examined. It is found that studying a specific difference of the g-factors of B- and H-like ions of the same spinless isotope in the Pb region to the currently accessible experimental accuracy of 7 x 10(-10) would lead to a determination of the fine structure constant to an accuracy which is better than that of the currently accepted value. Further improvements of the experimental and theoretical accuracy could provide a value of the fine structure constant which is several times more precise than the currently accepted one.