Relativistic all-order calculations of Th,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi>Th</mml:mi></mml:mrow><mml:mo>+</mml:mo></mml:msup></mml:math>, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi>Th</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:math>atomic properties

Safronova, M. S.; Safronova, U. I.; Clark, Charles W.

doi:10.1103/physreva.90.032512

Cited by 24 publications

(26 citation statements)

References 52 publications

(79 reference statements)

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“…Motivated by 229 Th nuclear clock search, the method of valence configuration-interaction (CI) with all-order valence-core corrections was used by M. S. Safronova et al [9] to calculate energies of Th I, Th II, and Th III, but unfortunately transition probabilities or lifetimes for Th II were not presented. This could be due to complexity and strong mixing of Th II levels that require precision beyond available in ab initio theory.…”

Section: Introductionmentioning

confidence: 99%

CI-MBPT and Intensity-Based Lifetime Calculations for Th II

Savukov

2020

Atoms

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Lifetime calculations of Th II J = 1.5 and 2.5 odd states are performed with configuration–interaction many-body perturbation theory (CI-MBPT). For many J = 2.5 states, lifetimes are quite accurate, but two pairs of J = 2.5 odd states and many groups of J = 1.5 states are strongly mixed, making theoretical predictions unreliable. To solve this problem, a method based on intensities is used. To relate experimental intensities to lifetimes, two parameters, one an overall coefficient of proportionality for transition rates and one temperature of the Boltzmann distribution of populations, are introduced and fitted to minimize the deviation between theoretical and intensity-derived lifetimes. For strongly mixed groups of states, the averaged lifetimes obtained from averaged transition rates were used instead of individual lifetimes in the fit. Close agreement is obtained. Then intensity branching ratios are used to extract individual lifetimes for the strongly mixed states. The resulting lifetimes are compared to available directly measured lifetimes and reasonable agreement is found, considering limited accuracy of intensity measurements. The method of intensity-based lifetime calculations with fit to theoretical lifetimes is quite general and can be applied to many complex atoms where strong mixing between multiple states exists.

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Section: Introductionmentioning

confidence: 99%

CI-MBPT and Intensity-Based Lifetime Calculations for Th II

Savukov

2020

Atoms

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“…Detailed theoretical investigations of the thorium electronic shell were performed to lay the foundations for the experimental studies of the EB process [83,301]. At PTB the thorium ions are produced by laser ablation [423] and stored in a linear Paul trap [422].…”

Section: 43mentioning

confidence: 99%

The $$^{229}$$Th isomer: prospects for a nuclear optical clock

Wense

2020

Eur. Phys. J. A

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The proposal for the development of a nuclear optical clock has triggered a multitude of experimental and theoretical studies. In particular the prediction of an unprecedented systematic frequency uncertainty of about $$10^{-19}$$ 10 - 19 has rendered a nuclear clock an interesting tool for many applications, potentially even for a re-definition of the second. The focus of the corresponding research is a nuclear transition of the $$^{229}$$ 229 Th nucleus, which possesses a uniquely low nuclear excitation energy of only $$8.12\pm 0.11$$ 8.12 ± 0.11 eV ($$152.7\pm 2.1$$ 152.7 ± 2.1 nm). This energy is sufficiently low to allow for nuclear laser spectroscopy, an inherent requirement for a nuclear clock. Recently, some significant progress toward the development of a nuclear frequency standard has been made and by today there is no doubt that a nuclear clock will become reality, most likely not even in the too far future. Here we present a comprehensive review of the current status of nuclear clock development with the objective of providing a rather complete list of literature related to the topic, which could serve as a reference for future investigations.

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“…3 Searching for the nuclear isomer transition of 229 Th presents a significant challenge. Any charge state should exhibit the isomer transition, 12 including neutral, single-, double-and triple-charged 229 Th. However, triplecharged 229 Th is especially attractive because of the availability of a forbidden transition and because its ionization energy is much higher than the isomeric transition energy.…”

Section: Introductionmentioning

confidence: 99%

“…18 Figure 1. Schematic picture of the linear ion trap for the optical spectrometry of electron and nuclear transitions (a) and overall view of constructed instrument (b): 1, vacuum chamber; 2, ion source; 3, linear ion trap; 4-7, lasers for first-stage cooling (not currently installed); 8 and 9, lasers for second-stage cooling and excitation of fluorescence (not currently installed); 10, a tunable laser for an isomeric transition search in the region of VUV (not currently installed); 11, a CCD camera (not currently installed); 12 Producing Th 3+ and its loading into the ion trap for subsequent spectroscopic study poses a significant challenge because thorium is a refractory metal with a high melting point and low vapor pressure. [19][20][21] Besides, generating multiply ionized species is much less efficient than generating singly ionized ones.…”

Section: Introductionmentioning

confidence: 99%

Multisectional Linear Ion Trap and Novel Loading Method for Optical Spectroscopy of Electron and Nuclear Transitions

Сысоев

Troyan

Borisyuk

et al. 2015

Eur J Mass Spectrom (Chichester)

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There is a growing need for the development of atomic and nuclear frequency standards because of the important contribution of methods for precision time and frequency measurements to the development of fundamental science, technology and the economy. It is also conditioned by their potential use in optical clocks and quantum logic applications. It is especially important to develop a universal method that could allow one to use ions of most elements effectively (including ones that are not easily evaporated) proposed for the above-mentioned applications. A linear quadrupole ion trap for the optical spectroscopy of electron and nuclear transitions has been developed and evaluated experimentally. An ion source construction is based on an ultra-high vacuum evaporator in which a metal sample is subjected to an electron beam of energy up to 1 keV, resulting in the appearance of gaseous atoms and ions of various charge state.The linear ion trap consists of five successive quadrupole sections including an entrance quadrupole section, quadrupole mass filter, quadrupole ion guide, ion-trap section and exit quadrupole section. The same radiofrequency but a different direct current voltage feeds the quadrupole sections. The instrument allows the mass-and energy-selected trapping of ions from ion beams of various intensities and their localization in the area of laser irradiation. The preliminary results presented show that the proposed instrument and methods allow one to produce effectively up to triply charged thorium ions as well as to trap ions for future spectroscopic study. The instrument is proposed for future use in optical clocks and quantum logic application development.

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Relativistic all-order calculations of Th,Th+, andTh2+atomic properties

Cited by 24 publications

References 52 publications

CI-MBPT and Intensity-Based Lifetime Calculations for Th II

CI-MBPT and Intensity-Based Lifetime Calculations for Th II

The $$^{229}$$Th isomer: prospects for a nuclear optical clock

Multisectional Linear Ion Trap and Novel Loading Method for Optical Spectroscopy of Electron and Nuclear Transitions

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