Atomic Hyperfine Structure Research Articles

Hyperfine spectra of surface atoms

Magnetic Resonance The interaction of nuclei with nonzero spin with electron spins creates small electronic energy. With a scanning tunneling microscope tip, Willke et al. measured these hyperfine interactions for iron and titanium atoms that were manipulated on a magnesium oxide surface. The tip was also used to measure electron paramagnetic resonance spectra. The hyperfine structure of single atoms was sensitive to the binding site of the atom as well as its position relative to other magnetic atoms. Science , this issue p. [336][1] [1]: /lookup/doi/10.1126/science.aat7047

Hyperfine interaction with the Th229 nucleus and its low-lying isomeric state

The thorium nucleus with mass number $A=229$ has attracted much interest because its extremely low lying first excited isomeric state at about $8$eV opens the possibility for the development of a nuclear clock. However, neither the exact energy of this nuclear isomer nor properties, such as nuclear magnetic dipole and electric quadrupole moment are known to a high precision so far. The latter can be determined by investigating the hyperfine structure of thorium atoms or ions. Due to its electronic structure and the long lifetime of the nuclear isomeric state, Th$^{2+}$ is especially suitable for such kind of studies. In this letter we present a combined experimental and theoretical investigation of the hyperfine structure of the $^{229}$Th$^{2+}$ ion in the nuclear ground and isomeric state. A very good agreement between theory and experiment is found for the nuclear ground state. Moreover, we use our calculations to confirm the recently presented experimental value for the nuclear magnetic dipole moment of the thorium nuclear isomer, which was in contradiction to previous theoretical studies.

Correlation trends in the magnetic hyperfine structure of atoms: A relativistic coupled-cluster case study

The role of electron correlation in the hyperfine structure of alkali metals and alkaline earth metal monopositive ions in their ground electronic configuration is investigated using the Z-vector method in a relativistic coupled-cluster regime within the singles and doubles approximation. The systematic effects of core-correlating functions, polarization of core electrons, and high-lying virtual functions on core electrons correlation are studied. The study reveals that the core-correlating function plays a significant role in core polarization and thus is very important for precise calculation of the wave function near the nuclear region. The inner-core electrons (1s-2p) require very high virtual energy functions for proper correlation. Therefore, the all-electron correlation treatment and the inclusion of higher-energy virtual functions are the key factors for precise calculation of the hyperfine structure constant of atoms. Our calculated values are in excellent agreement with the available experimental values, which also implies that the wave function produced by the Z-vector method is accurate enough for further calculation of the parity- and time-reversal symmetry-violating properties in atoms and molecules.

Nonlinear Zeeman effects in the cavity-enhanced emission of polarised photons

We theoretically and experimentally investigate nonlinear Zeeman (NLZ) effects within a polarised single-photon source that uses a single 87Rb atom strongly coupled to a high finesse optical cavity. The breakdown of the atomic hyperfine structure in the transition manifold for intermediate strength magnetic fields is shown to result in asymmetric and, ultimately, inhibited operation of the polarised atom–photon interface. The coherence of the system is considered using Hong–Ou–Mandel interference of the emitted photons. This informs the next steps to be taken and the modelling of future implementations, based on feasible cavity designs operated in regimes minimising NLZ effects, is presented and shown to provide improved performance.

Determination of hyperfine structure constants of 5D5/2 and 7S1/2 states of rubidium in cascade atomic system

We present a method to precisely determine the hyperfine structure constants of the rubidium 5D5/2 and 7S1/2 states in a cascade atomic system. The probe laser is coupled to the 5S1/2→5P3/2 hyperfine transition, while the coupling laser is scanned over the 5P3/2→5D5/2(7S1/2) transition. The high-resolution double-resonance optical pumping spectra are obtained with two counter-propagating laser beams acting on rubidium vapor. The hyperfine splitting structures are accurately measured by an optical frequency ruler based on the acousto-optic modulator, thus, the magnetic dipole hyperfine coupling constant A and quadrupole coupling constant B are determined. It is of great significance for the atomic hyperfine structure and fundamental physics research.

Influence of the dynamic Stark effect on long-term frequency stability of a self-oscillating magnetometer with laser-pumped alkali atoms

This paper presents the results of investigation Stark shift effect influence on the long-term stability of a dual scheme of quantum magnetometers. Such scheme allows suppressing Stark shift components when a certain pumping light polarization is applied. As a result, long-term stability of a quantum sensor increases. However, when low-frequency (LF) and microwave fields are attached to a single vapor cell a coherence circulation in hyperfine structure of alkali atoms takes place. Physical origin of this effect is associated with the so called “dressed” atom theory, when atom is “dressed” by LF field. It yields in multiphoton absorption and resonance frequency shift. First estimates for this shift based on density matrix evolution formalism are provided in the paper.

Theoretical prediction of the fine and hyperfine structure of heavy muonic atoms

Precision calculations of the fine and hyperfine structure of muonic atoms are performed in a relativistic approach and results for muonic 205 Bi, 147 Sm, and 89 Zr are presented. The hyperfine structure due to magnetic dipole and electric quadrupole splitting is calculated in first order perturbation theory, using extended nuclear charge and current distributions. The leading correction from quantum electrodynamics, namely vacuum polarization in Uehling approximation, is included as a potential directly in the Dirac equation. Also, an effective screening potential due to the surrounding electrons is calculated, and the leading relativistic recoil correction is estimated.

Comprehensive atomic wavelengths, energy levels, and hyperfine structure for singly ionized iron-group elements

We summarize recent work at the National Institute of Standards and Technology and Imperial College London on wavelengths, hyperfine structure, energy levels, and analysis of singly ionized iron-group elements of astrophysical interest.

The correction of hadronic nucleus polarizability to hyperfine structure of light muonic atoms

The calculation of hadronic polarizability contribution of the nucleus to hyperfine structure of muonic hydrogen and helium is carried out within the unitary isobar model and experimental data on the polarized structure functions of deep inelastic lepton-proton and lepton-deuteron scattering. The calculation of virtual absorption cross sections of transversely and longitudinally polarized photons by nucleons in the resonance region is performed in the framework of the program MAID.

Charge Radii of Neutron Deficient ^{52,53}Fe Produced by Projectile Fragmentation.

Bunched-beam collinear laser spectroscopy is performed on neutron deficient ^{52,53}Fe prepared through in-flight separation followed by a gas stopping. This novel scheme is a major step to reach nuclides far from the stability line in laser spectroscopy. Differential mean-square charge radii δ⟨r^{2}⟩ of ^{52,53}Fe are determined relative to stable ^{56}Fe as δ⟨r^{2}⟩^{56,52}=-0.034(13) fm^{2} and δ⟨r^{2}⟩^{56,53}=-0.218(13) fm^{2}, respectively, from the isotope shift of atomic hyperfine structures. The multiconfiguration Dirac-Fock method is used to calculate atomic factors to deduce δ⟨r^{2}⟩. The values of δ⟨r^{2}⟩ exhibit a minimum at the N=28 neutron shell closure. The nuclear density functional theory with Fayans and Skyrme energy density functionals is used to interpret the data. The trend of δ⟨r^{2}⟩ along the Fe isotopic chain results from an interplay between single-particle shell structure, pairing, and polarization effects and provides important data for understanding the intricate trend in the δ⟨r^{2}⟩ of closed-shell Ca isotopes.

Laser spectroscopy of atoms in superfluid helium for the measurement of nuclear spins and electromagnetic moments of radioactive atoms

A new laser spectroscopic method named “OROCHI (Optical RI-atom Observation in Condensed Helium as Ion catcher)” has been developed for deriving the nuclear spins and electromagnetic moments of low-yield exotic nuclei. In this method, we observe atomic Zeeman and hyperfine structures using laser-radio-frequency/microwave double-resonance spectroscopy. In our previous works, double-resonance spectroscopy was performed successfully with laser-sputtered stable atoms including non-alkali Au atoms as well as alkali Rb and Cs atoms. Following these works, measurements with 84−87Rb energetic ion beams were carried out in the RIKEN projectile fragment separator (RIPS). In this paper, we report the present status of OROCHI and discuss its feasibility, especially for low-yield nuclei such as unstable Au isotopes.

DIVISION B COMMISSION 14 WORKING GROUP: ATOMIC DATA

This report summarizes laboratory measurements of atomic wavelengths, energy levels, hyperfine and isotope structure, energy level lifetimes, and oscillator strengths. Theoretical calculations of lifetimes and oscillator strengths are also included. The bibliography is limited to species of astrophysical interest. Compilations of atomic data and internet databases are also included. Papers are listed in the bibliography in alphabetical order, with a reference number in the text.

Micron-thick spectroscopic cells for studying the Paschen-Back regime on the hyperfine structure of cesium atoms

It is shown that the use of spectroscopic cells of micron thickness (L = 10–50 μm) allows one to effectively study the behavior of individual levels of the Cs D2 line in strong magnetic fields up to 9 kG. In particular, the absorption spectrum of Cs excited by circularly polarized light in fields above 8 kG consists of two fully separated groups, each containing eight atomic transitions. The intensities of atomic transitions and their frequency slopes (vs. magnetic field) in each group are almost the same. The physical explanation for the observed features is given; in particular, it is shown that one of the 54 possible atomic transitions in moderate magnetic fields (denoted Fg = 4, mF = 4 → Fe = 5, mF = 5) has unique characteristics that make it possible to predict the intensities and frequency slopes of seven atomic transitions in the same group. Practical applications of devices based on micrometric-thin cells in strong magnetic fields are considered.

Paschen-Back effect involving atomic fine and hyperfine structure states

AbstractThe linear polarization in spectral lines produced by coherent scattering is significantly modified by the quantum interference between the atomic states in the presence of a magnetic field. When magnetic fields produce a splitting which is of the order of or greater than the fine or hyperfine structure splittings, we enter the Paschen-Back effect (PBE) regime, in which the magnetic field dependence of the Zeeman splittings and transition amplitudes becomes non-linear. In general, PBE occurs for sufficiently strong fields when the fine structure states are involved and for weak fields in the case of hyperfine structure states. In this work, we apply the recently developed theory of PBE in the atomic fine and hyperfine structure states including the effects of partial frequency redistribution to the case of Li i 6708 Å doublet. We explore the signatures of PBE in a single scattering event and their applicability to the solar magnetic field diagnostics.

Route to observing topological edge modes in ultracold fermions

We show how to exploit the rich hyperfine structure of fermionic alkali atoms to produce a quasi-1D topological superfluid while avoiding excessive heating from off-resonant scattering. We model interacting fermions where four hyperfine states are coupled by a variety of optical and microwave fields. We calculate the local density of states in a trap, finding regimes with zero energy topological edge modes. Heating rates in this system are significantly suppressed compared to simple Raman-induced spin-orbit coupling approaches.

Splitting of N-type optical resonance formed in Λ-system of 85Rb atoms in a strong transverse magnetic field

We study narrow-band N-type resonance formed in a Λ-system of 85Rb atoms. Even when thin (micrometer) optical cells are employed, N-type resonance has a high contrast. We used radiation of two cw diode lasers. Peculiarities of splitting of N-type resonance into six components in a strong transverse magnetic field are studied experimentally and theoretically and the conversion to the Paschen-Back regime on the hyperfine structure of 85Rb atoms is recorded.

Atomic hyperfine structure in micromaser physics

In this paper, we examine the effect of atomic hyperfine structure in micromaser physics which has not been considered so far. We examine both the case of completely degenerate hyperfine levels and small hyperfine splittings and show that the dynamics of the micromaser can be significantly modified. We also describe possible strategies to realize a quasi two-level system in the micromaser.

ATOMIC DATA: DIVISION XII / COMMISSION 14 / WORKING GROUP ATOMIC DATA

This report summarizes laboratory measurements of atomic wavelengths, energy levels, hyperfine and isotope structure, energy level lifetimes, and oscillator strengths. Theoretical calculations of lifetimes and oscillator strengths are also included. The bibliography is limited to species of astrophysical interest. Compilations of atomic data and internet databases are also included. Papers are listed in the bibliography in alphabetical order, with a reference number in the text.

Palladium–Hydrogen Complex in Silicon Observed by Electron Spin Resonance Measurement

We have investigated a palladium–hydrogen complex in silicon by electron spin resonance (ESR) measurement. A new ESR spectrum was detected in a sample diffused with palladium and hydrogen. The hyperfine structure of hydrogen atoms in the ESR spectrum shows that the spectrum originates from a palladium–hydrogen complex containing three hydrogen atoms (Pd–H3). The anisotropic g-value of Pd–H3 shows that the Pd–H3 complex has an anisotropic character of orthorhombic (C2v) symmetry. The calculated g-values of the Pd–H3 complex are g1 = 2.12, g2 = 2.10, and g3 = 2.03, and the g2 axis is along the <100 > direction. The anisotropic character of orthorhombic (C2v) symmetry results from a configuration consisting of one Pd atom at a substitutional site, two equivalent hydrogen atoms at interstitial sites along the <111 > direction, and one hydrogen atom at the next-nearest-neighbor interstitial site along the <100 >-twofold symmetry axis. We have also studied the dissociation of a platinum–hydrogen complex by thermal treatment. The activation energy for the dissociation of the Pd–H3 complex is estimated to be about 1.6 eV.

Supersonic sodium atomic beam hyperfine structure measurement orthogonally with dye laser R6G

Supersonic sodium atomic beam hyperfine structure measurement orthogonally with dye laser R6G