The Third Spectrum of Tantalum (Ta III): Fine and Hyperfine Structure

Azarov, V I; Tchang-Brillet, W. Ü. L.; Wyart, J.-F.; Meijer, Frans

doi:10.1238/physica.regular.067a00190

Cited by 22 publications

(24 citation statements)

References 47 publications

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“…No appreciable spin contamination was found for the different levels of theory for any of these states. The quartet-doublet excitation energies can be compared to experimental values (average of the spin-orbit levels for each state) of 0.381 eV for a 2 P(5d 3 ) excited state and 0.990 for a 2 D(5d 3 ) excited state, 22 such that the density functional theoretical values fall between these two values. The experimental excitation energy for the 4 F(6s 1 5d 2 ) state is 0.732 eV, in reasonable agreement with the theoretical values.…”

Section: Theoretical Calculationsmentioning

confidence: 99%

Energetics and Mechanisms of C−H Bond Activation by a Doubly Charged Metal Ion: Guided Ion Beam and Theoretical Studies of Ta²⁺+ CH₄

2008

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A guided ion beam tandem mass spectrometer is used to study the kinetic-energy dependence of doubly charged atomic tantalum cations (Ta(2+)) reacting with CH4 and CD4. As for the analogous singly charged system, the dehydrogenation reaction to form TaCH2(2+) + H2 is exothermic. The charge-transfer reaction to form Ta(+) + CH4(+) and the charge-separation reaction to form TaH(+) + CH3(+) are also observed at low energies in exothermic processes, as is a secondary reaction of TaCH2(2+) to form TaCH3(+) + CH3(+). At higher energies, other doubly charged products, TaC(2+) and TaCH3(2+), are observed, although no formation of TaH(2+) was observed. Modeling of the endothermic cross sections provides 0 K bond dissociation energies (in electronvolts) of D0(Ta(2+)-C) = 5.42 +/- 0.19 and D0(Ta(2+)-CH3) = 3.40 +/- 0.16. These experimental bond energies are in poor agreement with density functional calculations at the B3LYP/HW+/6-311++G(3df,3p) level of theory. However, the Ta(2+)-C bond energy is in good agreement with calculations at the QCISD(T) level of theory, and the Ta(2+)-CH3 bond energy is in good agreement with density functional calculations at the BHLYP level of theory. Theoretical calculations reveal the geometric and electronic structures of all product ions and are used to map the potential energy surface, which describes the mechanism of the reaction and key intermediates. Both experimental and theoretical results suggest that TaH(+), TaCH2(2+), and TaCH3(2+) are formed through a H-Ta(2+)-CH3 intermediate.

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Section: Theoretical Calculationsmentioning

confidence: 99%

Energetics and Mechanisms of C−H Bond Activation by a Doubly Charged Metal Ion: Guided Ion Beam and Theoretical Studies of Ta²⁺+ CH₄

2008

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“…For reasons discussed in our previous papers (see, e.g., Biémont andQuinet 2003 andBiémont 2005), the HFR approach (Cowan 1981) was adopted Azarov et al (2003).…”

Section: Hfr Calculationsmentioning

confidence: 99%

“…a Azarov et al (2003 model (including 5d 3 , 5d 2 6s, 5d6s 2 , 5d 2 6p and 5d6s6p) with seven-configuration calculations (adding 5f 3 and 6f 3 ), the effect on the lifetimes of the latter two configurations was estimated and found very small, the mean difference τ being smaller than 0.1%. Core-valence interactions were taken into account through a polarization model potential and a correction to the dipole operator following a well-established procedure (see, e.g., Quinet et al (1999)) giving rise to the so-called HFR + CPOL method.…”

Section: Hfr Calculationsmentioning

confidence: 99%

“…Ta III in particular suffers from the lack of accurate theoretical and experimental f-values or lifetimes. The only set of transition probabilities available in this ion is that reported by Azarov et al (2003) who calculated transition probabilities for the classified transitions appearing in the (5d 3 + 5d 2 6s + 5d6s 2 )-(5d 2 6p + 5d6s6p) transition array. Their calculations included only three odd and three even configurations, since the main purpose of their paper was to identify and classify the spectral lines.…”

Section: Introductionmentioning

confidence: 99%

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Radiative lifetime measurements and calculations in doubly ionized tantalum (Ta III)

Fivet¹,

Biémont²,

Engström³

et al. 2007

J. Phys. B: At. Mol. Opt. Phys.

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Radiative lifetimes of six odd-parity levels belonging to the 5d 2 6p configuration of doubly ionized tantalum (Ta III) have been measured using the time-resolved-laser-inducedfluorescence technique. Supporting theoretical calculations, including core-polarization effects, have been performed to model configuration interaction and to estimate branching fractions. The excellent agreement between the theoretical and experimental lifetimes allows us to assess the reliability of the 206 calculated transition probabilities. It is expected that this new set of results will be useful to astrophysicists for the investigation of the chemical composition of stars.

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“…The levels for Ta 2+ and Ta 3+ are found in Refs. . But the levels for the ions with higher charge seem to be absent.…”

Section: The Modelmentioning

confidence: 95%

The pressure, internal energy, and conductivity of tantalum plasma

Apfelbaum

2017

Contrib. Plasma Phys

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The pressure, internal energy, and conductivity of a tantalum plasma were calculated at the temperatures 10–100 kK and densities less than 3 g/cm3. The plasma composition, pressure, and internal energy were obtained by means of the corresponding system of the coupled mass action law equations. We have considered atom ionization up to +3. The conductivity was calculated within the relaxation time approximation. Comparisons of our results with available measurements and calculation data show good agreement in the area of correct applicability of the present model.

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The Third Spectrum of Tantalum (Ta III): Fine and Hyperfine Structure

Cited by 22 publications

References 47 publications

Energetics and Mechanisms of C−H Bond Activation by a Doubly Charged Metal Ion: Guided Ion Beam and Theoretical Studies of Ta²⁺+ CH₄

Energetics and Mechanisms of C−H Bond Activation by a Doubly Charged Metal Ion: Guided Ion Beam and Theoretical Studies of Ta²⁺+ CH₄

Radiative lifetime measurements and calculations in doubly ionized tantalum (Ta III)

The pressure, internal energy, and conductivity of tantalum plasma

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The Third Spectrum of Tantalum (Ta III): Fine and Hyperfine Structure

Cited by 22 publications

References 47 publications

Energetics and Mechanisms of C−H Bond Activation by a Doubly Charged Metal Ion: Guided Ion Beam and Theoretical Studies of Ta2++ CH4

Energetics and Mechanisms of C−H Bond Activation by a Doubly Charged Metal Ion: Guided Ion Beam and Theoretical Studies of Ta2++ CH4

Radiative lifetime measurements and calculations in doubly ionized tantalum (Ta III)

The pressure, internal energy, and conductivity of tantalum plasma

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Product

Resources

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Energetics and Mechanisms of C−H Bond Activation by a Doubly Charged Metal Ion: Guided Ion Beam and Theoretical Studies of Ta²⁺+ CH₄

Energetics and Mechanisms of C−H Bond Activation by a Doubly Charged Metal Ion: Guided Ion Beam and Theoretical Studies of Ta²⁺+ CH₄