Lamb shifts and hyperfine structure in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Li</mml:mi></mml:mrow><mml:mrow /><mml:mrow><mml:mo>+</mml:mo></mml:mrow><mml:mrow /><mml:mrow /><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>6</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmulti

Riis, Erling; Sinclair, Alastair G.; Poulsen, O.; Drake, G. W. F.; Rowley, W. R. C.; Levick, A. P.

doi:10.1103/physreva.49.207

Cited by 122 publications

(62 citation statements)

References 48 publications

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“…We find that both the one-body spin-orbit, and the two-body spin-spin and spin-other-orbit interactions must be included, in order to accurately reproduce the strengths. In the case of the 2S state, this hyperfine mixing is also important for hyperfine structure, as shown by Riis et al [26], but its contribution to the transition strength is negligible in the present work.…”

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confidence: 65%

Hyperfine Suppression of2 S13−3 PJ3Transitions in
Sulai
¹
,
Wu
²
,
Bishof
³

et al. 2008
Phys. Rev. Lett.
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Two anomalously weak transitions within the 2 3 S1 − 3 3 PJ manifolds in 3 He have been identified. Their transition strengths are measured to be 1,000 times weaker than that of the strongest transition in the same group. This dramatic suppression of transition strengths is due to the dominance of the hyperfine interaction over the fine structure interaction. An alternative selection rule based on IS -coupling (where the nuclear spin is first coupled to the total electron spin) is proposed. This provides qualitative understanding of the transition strengths. It is shown that the small deviations from the IS -coupling model are fully accounted for by an exact diagonalization of the strongly interacting states.PACS numbers: 31.30. Gs, 32.10.Fn, 32.70.Fw, 32.70.Cs Persistent efforts in both theory and experiment have yielded increasingly precise understanding of the helium atom. Due to its simplicity, the helium atom has been a proving ground for precision atomic measurements and calculations of few-body quantum systems. The knowledge gained from this effort is used to test bound-state quantum electrodynamics [1,2,3], determine the fine structure constant [4,5], and explore exotic nuclear structure [6,7,8,9]. We report results of a combined theoretical and experimental study on the strengths of 2 3 S 1 − 3 3 P J transitions in 3 He. Surprisingly, we observe that the strengths of two "allowed" transitions, 22 ), are 1,000 times weaker than that of the strongest transition 22 ). The level scheme showing these transitions is presented in Fig 1. This dramatic suppression of transition strengths is due to a rare atomic phenomenon: within the 3 3 P manifold, the hyperfine interaction is comparable to or even stronger than the fine structure interaction. Consequently the conventional model based on LS -coupling is no longer applicable. Rather, we find that an alternative model where the fine structure interaction is treated as a perturbation on states obtained by first coupling nuclear spin to the total electron spin provides a good qualitative explanation of the observed suppression. We refer to this coupling scheme as IS -coupling. We start by discussing the details of the experiment and compare the data with the predictions from the different coupling schemes. Finally, we discuss an exact diagonalization method to account for the small differences between experiment and the IScoupling scheme.We measure the ratio of transition strengths using a cross-beam laser induced fluorescence method. A beam of metastable helium atoms in the 2 3 S 1 state is prepared in a liquid-nitrogen cooled RF-driven discharge. A retro-reflected beam of linearly polarized 389 nm light is The large hyperfine splitting with respect to the fine structure splitting is evident. With a nuclear spin I = 1/2 for 3 He, the levels are designated by the familiar term symbols, with J = L + S, F = J + I on the left. The levels are labeled on the right using the quantum numberincident perpendicular to the atomic beam. The polarization of the light is alon...

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confidence: 65%

Hyperfine Suppression of2 S13−3 PJ3Transitions in
Sulai
¹
,
Wu
²
,
Bishof
³

et al. 2008
Phys. Rev. Lett.
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“…For lithium, although the rms nuclear radii of the stable species 6 Li and 7 Li are determined at the 1% level ͓2͔, for unstable 8 Li, 9 Li, and 11…”

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Lithium isotope shifts as a measure of nuclear size

Zhou

Drake

2000

Phys. Rev. A

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The isotope shifts for 2 2 P J -2 2 S and 3 2 S -2 2 S transition energies in lithium are calculated variationally in Hylleraas coordinates, including nonrelativistic, relativistic, and QED terms up toand O(␣ 3 /M ) atomic units, and the lowest-order finite nuclear size correction. With highprecision isotope shift measurements, our results can potentially yield a precise determination of the nuclear charge radius for different isotopes of lithium, and especially for the exotic 11 Li ''halo'' isotope. For the case of 7 Li-6 Li, using the nuclear charge radii from nuclear scattering data, our calculated isotope shifts for the 2 2 P 1/2 -2 2 S, 2 2 P 3/2 -2 2 S, and 3 2 S -2 2 S transitions are 10 534.31(61)(6) MHz, 10 534.70(61)(6) MHz, and 114 54.31(39)(5) MHz, respectively, where the first brackets indicate the uncertainties due to the nuclear charge radii, and the second brackets indicate the computational uncertainties. The experimental isotope shifts are inconsistent with each other and with theory for these transitions.

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“…The difference in squared charge radii between 6 Li and 7 Li can also be obtained from the isotope shift measurement of 2 3 S-2 3 P J transitions in Li by Riis et al [25]. Taking the weighted average value and theoretical isotope shift from Ref.…”

Section: H Y S I C a L R E V I E W L E T T E R S Week Ending 29 Septementioning

confidence: 99%

Isotope Shift of the3 S1/22−2 S1/2
Puchalski
¹
,
Moro
²
,
Pachucki
³

2006
Phys. Rev. Lett.
82
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High precision calculation of the isotope shift of the 3 2 S 1=2 -2 2 S 1=2 transition in lithium is presented. The wave function and matrix elements of relativistic operators are obtained by using recursion relations. Apart from the relativistic contribution, we obtain the nuclear polarizability correction for 11 Li. The resulting difference of the squared charge radii 11 The recent advances in precise spectroscopy of atomic systems make possible the determination of nuclear charge radii from isotope shift measurements [1][2][3][4]. In spite of the fact that the nuclear size is 5 orders of magnitude smaller than the atomic size, the achieved experimental precision for transition frequencies allows one to determine nuclear charge radii much more accurately than from electron scattering measurements. This, however, requires the theoretical calculations to be performed with high relative precision, for example, at least 10 ÿ6 for lithium isotopes. The accuracy of theoretical predictions achieved for hydrogen [5] leads to the determination of the proton charge radius [5,6], which is far more accurate than from the electron scattering measurements. A similar experimental accuracy achieved for deuterium allowed one to determine very accurately the deuteron radius [1]. Surprisingly, the atomic measurements lead to a slightly different value from the electron scattering determination, which stimulated a reanalysis of electron scattering data. What makes the deuteron different from other typical nuclei is its low binding energy of about 2.226 MeV. Such a soft nucleus is distorted by a surrounding electron, which leads to a shift in atomic transition frequencies. Even smaller is the twoneutron separation energy in 11 Li [7], which indicates the possible significance of nuclear structure effects on the isotope shift.In this Letter, we present significantly improved calculations of finite nuclear mass contributions to the isotope shift in the lithium 3 2 S 1=2 -2 2 S 1=2 transition. Such calculations have already been performed by Yan and Drake in Refs. [8][9][10] and were used to determine nuclear charge radii of various lithium isotopes on the basis of recent isotope shift measurements [3,4]. Our result for the relativistic recoil correction is about 10 times smaller than that reported in Refs. [8,9]. Apart from the known nonrelativistic, leading relativistic, and QED corrections, we include higher order recoil corrections and the nuclear polarizability effect E pol , the last being significant for the 11 Li nucleus. Finally, we use our combined results to calculate new nuclear charge radii for the lithium isotopes, taking the experimental isotope shift results from Refs. [3,4].Let us denote ÿ =M. The expansion of an energy level in the fine structure constant iswhere E fs is the nuclear finite size correction, and m, M, are the electron, nucleus, and the reduced mass, respectively. In the following, we obtain these expansion coefficients. The nonrelativistic Hamiltonian of the lithium atom in atomic units is

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Lamb shifts and hyperfine structure inLi+6and

Cited by 122 publications

References 48 publications

Hyperfine Suppression of2 S13−3 PJ3Transitions in
Sulai
¹
,
Wu
²
,
Bishof
³

et al. 2008
Phys. Rev. Lett.
Self Cite
8
1
14
0
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Hyperfine Suppression of2 S13−3 PJ3Transitions in
Sulai
¹
,
Wu
²
,
Bishof
³

et al. 2008
Phys. Rev. Lett.
Self Cite
8
1
14
0
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Lithium isotope shifts as a measure of nuclear size

Isotope Shift of the3 S1/22−2 S1/2
Puchalski
¹
,
Moro
²
,
Pachucki
³

2006
Phys. Rev. Lett.
82
8
122
2
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Lamb shifts and hyperfine structure inLi+6and

Cited by 122 publications

References 48 publications

Hyperfine Suppression of2 S13−3 PJ3Transitions inSulai1, Wu2, Bishof3 et al. 2008Phys. Rev. Lett.Self Cite81140View full textAdd to dashboardCite

Hyperfine Suppression of2 S13−3 PJ3Transitions inSulai1, Wu2, Bishof3 et al. 2008Phys. Rev. Lett.Self Cite81140View full textAdd to dashboardCite

Lithium isotope shifts as a measure of nuclear size

Isotope Shift of the3 S1/22−2 S1/2Puchalski1, Moro2, Pachucki3 2006Phys. Rev. Lett.8281222View full textAdd to dashboardCite

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Hyperfine Suppression of2 S13−3 PJ3Transitions in
Sulai
¹
,
Wu
²
,
Bishof
³

et al. 2008
Phys. Rev. Lett.
Self Cite
8
1
14
0
View full text Add to dashboard Cite

Hyperfine Suppression of2 S13−3 PJ3Transitions in
Sulai
¹
,
Wu
²
,
Bishof
³

et al. 2008
Phys. Rev. Lett.
Self Cite
8
1
14
0
View full text Add to dashboard Cite

Isotope Shift of the3 S1/22−2 S1/2
Puchalski
¹
,
Moro
²
,
Pachucki
³

2006
Phys. Rev. Lett.
82
8
122
2
View full text Add to dashboard Cite