Radiative lifetimes of some group II ions by the Hanle effect in a fast-flowing helium afterglow

Rambow, Frederick H.K.; Schearer, L. D.

doi:10.1103/physreva.14.1735

Cited by 39 publications

(15 citation statements)

References 10 publications

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“…The two most recent experiments [66,67] gave lifetimes that are 2% larger than the DFCP lifetimes and 3% larger than the MBPT-SD lifetimes. Older Hanle effect experiments [68,69] gave lifetimes closer to the MBPT-SD and DFCP lifetimes. Measurements of the branching ratios of the 4p 3/2 state yield a picture where the MBPT-SD calculations largely agree with experiment while the DFCP tends to overestimate the contributions of the decays to the 3d J levels.…”

Section: A Reduced Matrix Elementsmentioning

confidence: 99%

Dynamic polarizabilities for the low-lying states of Ca+

et al. 2013

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The dynamic polarizabilities of the 4s, 3d and 4p states of Ca + , are calculated using a relativistic structure model. The wavelengths at which the Stark shifts between different pairs of transitions are zero are computed. Experimental determination of the magic wavelengths can be used to estimate the ratio of the f 3d J →4p J ′ and f4s 1/2 →4p J ′ oscillator strengths. This could prove valuable in developing better atomic structure models and in particular lead to improved values of the polarizabilities needed in the evaluation of the blackbody radiation shift of the Ca + ion.

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Section: A Reduced Matrix Elementsmentioning

confidence: 99%

Dynamic polarizabilities for the low-lying states of Ca+

et al. 2013

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“…where χ i is the target ion wave function in a specific state LS i , θ i is the wave function of the free electron, Φ j are short range Ansbacher et al (1985), i Gosselin et al (1988b), j Smith & Gallagher (1966), k Rambow & Schearer (1976), l Liaw (1995), m Jin & Church (1993). Table 5.…”

Section: Scattering Calculationsmentioning

confidence: 99%

Atomic data from the IRON project

Meléndez

Bautista²,

Badnell

2007

A&A

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Aims. This work reports radiative transition rates and electron impact excitation rate coefficients for levels of the n = 3, 4, 5, 6, 7, 8 configurations of Ca ii.Methods. The radiative data were computed using the Thomas-Fermi-Dirac central potential method in the frozen core approximation and includes the polarization interaction between the valence electron and the core using a model potential. This method allows for configuration interactions (CI) and relativistic effects in the Breit-Pauli formalism. Collision strengths in LS-coupling were calculated in the close coupling approximation with the R-matrix method. Then, fine structure collision strengths were obtained by means of the intermediate-coupling frame transformation (ICFT) method which accounts for spin-orbit coupling effects.Results. We present extensive comparisons with the most recent calculations and measurements for Ca ii as well as a comparison between the core polarization results and the "unpolarized" values. We find that core polarization affects the computed lifetimes by up to 20%. Our results are in very close agreement with recent measurements for the lifetimes of metastable levels. The present collision strengths were integrated over a Maxwellian distribution of electron energies and the resulting effective collision strengths are given for a wide range of temperatures. Our effective collision strengths for the resonance transitions are within ∼11% from previous values derived from experimental measurements, but disagree with later computations using the distorted wave approximation.

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“…Equation (18) (6) Hanle effect [22] " These values are taken for the calculation of the 2p3/2 deorientation rate FI((S~)=0) at zero 2S1/z signal calculation using only the repulsive exchange interaction gives much better results for the Rb atom and the Sr § ion, indicating that the exchange potential is predominant in the 2P3/z depolarization by He in both cases [18]. The slight decrease of the cross sections from He to Ne for the alkalis is not observed in the case of the alkaline earth ions.…”

Section: P3/2 Depolarization Cross Sectionsmentioning

confidence: 99%

Collisional relaxation of ionic2 P 3/2 excited states in rare gases

Buttler

Weber

1978

Z Physik A

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Optical pumping with the D2 line is used to study the depolarization of the first excited 2p3/2 states of alkaline earth ions and Yb + ions in collisions with rare gas atoms. The deorientation cross sections for the even isotopes ofBa + and Yb + ions are obtained (in units of 10-t6 cm2): rare gas He Ne Ar Kr Xe al (Ba + 6p 2p3/2 ) 79(11) 89 (13) 123 (18) 152 (22) 204(30) ax (Yb + 6p 2p3/2) 60(10) 62 (9) 107 (18) 133 (17) 167 (37) The cross sections are discussed in comparison with theoretical calculations and those of isoelectronic atoms. The comparison of the 2P3/2 relaxation of even and odd (I = 3/2) isotopes of Ba + allows to draw conclusions on the nature of the depolarization interaction.

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Radiative lifetimes of some group II ions by the Hanle effect in a fast-flowing helium afterglow

Cited by 39 publications

References 10 publications

Dynamic polarizabilities for the low-lying states of Ca+

Dynamic polarizabilities for the low-lying states of Ca+

Atomic data from the IRON project

Collisional relaxation of ionic2 P 3/2 excited states in rare gases

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