Isotope shifts of the ground state of neon: Refining the measurement results

Abstract—It has been revealed that the published results of measurements of the isotope shift of the ground state of even neon isotopes contain systematic errors. The errors are caused by the use of erroneous data regarding the absolute values of specific mass shifts of excited states and by the measurement errors of the isotope shifts themselves for transitions to the ground state. The isotope shift of the 2p⁵4s[3/2]₁ → 2p⁶(¹S₀) transition has been measured to be 2305 ± 20 MHz, the absolute specific mass shift of the 3p[3/2]₂: (2_р9) level has been determined to be 647 ± 10 MHz, and the isotope shift of the ground state has been found to be–3156 ± 30 MHz.     

Absolute frequency and isotope shift measurements of the cooling transition in singly ionized indium

We report greater than two orders of magnitude improvements in the absolute frequency and isotope shift measurements of the In⁺ 5s^{2 1}S₀ (F = 9/2)–5s5p ³P₁ (F = 11/2) transition near 230.6 nm. The laser-induced fluorescence from a single In⁺ in a radio-frequency trap is detected. The fourth-harmonic of a semiconductor laser is used as the light source. The absolute frequency is measured with the help of a frequency comb referenced to a Cs atomic clock. The resulting transition frequencies for isotopes ¹¹⁵In⁺ and ¹¹³In⁺ are measured to be 1 299 648 954.54(10) MHz and 1 299 649 585.36(16) MHz, respectively. The deduced cooling transition frequency difference is 630.82(19) MHz. By taking into account of the hyperfine interaction, the isotope shift is calculated to be 695.76(1.68) MHz.     

Hyperfine interactions in the alkaline-earth Sr ions by collinear fast beam laser spectroscopy

The magnetic dipole hyperfine structure constants of the⁸⁷SrII 5s²S_1/2 ground state and the 5p²P_1/2 excited state, and the isotope shifts of the ionic 5s²S_1/2 → 5p²P_1/2 resonance transition for all stable Sr isotopes, measured by collinear fast beam laser spectroscopy, are reported.     

Evolution from quasielastic to deep-inelastic transfer in the system132Xe+natFe§

The pronounced isotope shift of⁸⁷Sr versus⁸⁷Sr observed recently in 5sns¹S₀ Rydberg states reflects the singlet-triplet mixing solely caused by magnetic hyperfine interaction. Using semiempirical estimates for the hyperfine coupling constant a_{5 s} and the singlet-triplet splitting ΔE_ST (n) excellent agreement between experimental and calculated values is obtained.     

Specific mass shift of potassium 5P1/2 state

We have measured the isotope shift between ⁴¹K and ³⁹K in the 4s_1/2 → 5p_1/2 transition at 405 nm using saturation spectroscopy. Our measured isotope shift is 456.1 ± 0.8 MHz, implying a residual isotope shift (sum of specific mass shift and field shift) of −52.7 ± 0.8 MHz. We deduce a specific mass shift of −40 ± 5 MHz, which would imply that the 5p_1/2 state has a considerably larger specific mass shift than the 4p_1/2 state. We have in addition measured the 5p_1/2 hyperfine splitting for ⁴¹K.     

Isotope shifts in transitions between low-lying levels of Sr I by laser-atomic-beam spectroscopy

High-resolution laser-atomic-beam spectroscopy has been used to determine isotope shifts in five transitions between low-lying states of Sr I. With these results and existing data a parametric analysis of level isotope shifts has been performed. The transition isotope shifts have been separated into field shift and mass shift contributions with a King-plot procedure using model-independent nuclear charge equivalent radiiR _k from muonic x-ray measurements. Values for the mean-square nuclear charge radiiδ〈r ₂ 〉 have been calculated from the field shifts in the optical transitions 5s ^{2 1} S ₀-5s5p ³ P ₁ and 5s5p ³ P ₀-5s6s ³ S ₁ and compared with correspondingδ〈r ² 〉 values evaluated from muonic x-ray data.     

New neutron deficient isotopes with mass numbersA=136 and 145

High resolution laser-atomic-beam spectroscopy was applied to study crossed-second-order effects in the isotope shift of the terms 4f⁷5d6s a¹⁰D and a⁸D for¹⁵¹Eu-¹⁵³Eu. The term dependent effects lead to a difference in the isotope shift of the terms a¹⁰D and a⁸D of 415(20) MHz. The J dependent effects are interpreted through the use of one parameter z_5d for each term; z_5d(a¹⁰D)=41(7)MHz, z_5d(a⁸D)=50(26)MHz.     

Optical clock and ultracold collisions with trapped strontium atoms

With microkelvin neutral strontium atoms confined in an optical lattice, we have achieved a fractional resolution of better than 5×10^–15 on the ¹ S ₀–³ P ₀ doubly forbidden ⁸⁷Sr clock transition at 698 nm. Measurements of the clock line shifts as a function of experimental parameters indicate that the fractional uncertainties due to systematic shifts could be reduced below 10^–15. The ultrahigh spectral resolution permitted resolving the nuclear spin states of the clock transition at small magnetic fields, leading to measurements of the ³ P ₀ magnetic moment and metastable lifetime. In addition, photoassociation spectroscopy was performed on the narrow ¹ S ₀–³ P ₁ transition of ⁸⁸Sr, revealing the least-bound state, and showing promise for efficient optical tuning of the ground state scattering length and production of cold molecules.     

Accurate spectroscopy of Sr atoms

We report the frequency measurement with an accuracy in the 100 kHz range of several optical transitions of atomic Sr: 1S0-3P1 at 689 nm, 3P1-3S1 at 688 nm and 3P0-3S1 at 679 nm. Measurements are performed with a frequency chain based on a femtosecond laser referenced to primary frequency standards. They allowed the indirect determination with a 70 kHz uncertainty of the frequency of the doubly forbidden transition of 87Sr at 698 nm and in a second step its direct observation. Frequency measurements are performed for 88Sr and 87Sr, allowing the determination of 3P0, 3P1 and 3S1 isotope shifts, as well as the 3S1 hyperfine constants.     

Experimental and theoretical investigation of the isotope shift of the 4D level in atomic potassium

Doppler-free two-photon laser spectroscopic measurements in the deep red spectral region have been performed on the transition 4² S _1/2→4² D _J in the naturally abundant isotopes 39 and 41 of atomic potassium. The 4D level isotope shift, ?81±12 MHz was obtained by combining the current results with data from Rydberg-state spectroscopy. Many-body perturbation theoretical calculations of the specific mass shift in the measured state are also presented. With the use of Brueckner orbitals the value ?70 MHz was obtained in substantial agreement with the experimental result.     

Measurement of the isotope shift of the 63 P 1 ↔53 D 1 transition of ytterbium by using a diode oscillator fiber amplified laser

We demonstrated a Diode Oscillator Fiber Amplification (DOFA) system in order to study the 6³ P ₁ ?5³ D ₁ (1539 nm) transition line of a neutral ytterbium atom that is accessed by the stepwise excitation of the ground state. The frequency of the DOFA system was doubled by a MgO:PPLN crystal for the resonant excitation of the 6¹ S ₀ ?6³ P ₁ transition. The frequency of the second harmonic beam was stabilized to the 6¹ S ₀ ?6³ P ₁ transition of each isotope with the stability of about 2 MHz. We performed absorption spectroscopy on the 6³ P ₁ ?5³ D ₁ (1539 nm) transition after the velocity selective excitation by the frequency-doubled beam. The isotope shifts in the 6³ P ₁ ?5³ D ₁ (1539 nm) transition were directly measured for the first time. The relative isotope shifts from ¹⁷⁴Yb were measured as ?105.8 MHz and 109.7 MHz for ¹⁷⁶Yb and ¹⁷²Yb, respectively.     

Saturated absorption spectroscopy in the ultra-violet with a continuous-wave,frequency-doubled,ring dye laser; even isotope shifts on the 6d3D1-6p3P0 transition of HgI

A novel, single-frequency, continuous-wave, ring, dye laser with intra-cavity frequency-doubling has been developed, and used to carry out saturated absorption spectroscopy on the 6s6d³D₁-6s6p³P₀ transition of Hg I at 296.7 nm. Even isotope shifts have been measured by this technique on this transition and are: Hg204-202, 350 ± 10 MHz; Hg202-200, 345 ± 10 MHz; Hg200-198, 310 ± 10 MHz. The shift on transitions from the hyperfine state 6s6d³D₁ ($\text{F =}\text{3}\text{2}$) between Hg199 and Hg201 has also been measured, and is 225 ± 10 MHz.     

Levelcrossing experiments in the first excited1 P 1 states of the alkaline earths

The hyperfine structure of the lowest¹P₁ state of²⁵Mg,⁴³Ca,⁸⁷Sr,¹³⁵Ba and¹³⁷Ba have been measured by the level-crossing and anticrossing technique. The magnetic dipole and electric quadrupole coupling constants determined by these measurements are²⁵Mg(3s3p¹P₁):A=? 7.7(5) MHz; 16 MHz>B>0 MHz,⁴³Ca(4s4p¹P₁):A=? 15.3(4) MHz; ¦B¦<12 MHz,⁸⁷Sr (5s5p¹P₁:A=? 3.4(4) MHz;B=39(4) MHz,¹³⁵Ba(6s6p¹P₁):A=? 97.5(1.0) MHz;B=31(9)MHz,¹³⁷Ba(6s6p¹P₁):A=?109.2(1.2) MHz;B=51(12)MHz. The results have been compared with the predictions of the Breit-Wills theory of the two-electron hyperfine structure using the experimental data on the³P states. Large discrepancies have been observed which are due to different radial wave functions of thes andp electron in the triplet and singlet system. This effect has been taken into account by fitting the data with the aid of two additional parameters. That this procedure is justified is shown by an analysis of the fine structure splitting, the life times, and the isotopic shifts in thesp configurations of group II elements.     

Precision frequency measurement of visible intercombination lines of strontium

We report the direct frequency measurement of the visible 5s(2) 1S0-5s5p 3P1 intercombination line of strontium that is considered a possible candidate for a future optical-frequency standard. The frequency of a cavity-stabilized laser is locked to the saturated fluorescence in a thermal Sr atomic beam and is measured with an optical-frequency comb generator referenced to the SI second through a global positioning system signal. The 88Sr transition is measured to be at 434 829 121 311 (10) kHz. We measure also the 88Sr-86Sr isotope shift to be 163 817.4 (0.2) kHz.     

Precision ground state Hfs-separation of137Ba

High resolution two-photon spectroscopy was applied to investigate isotope shifts of Ssns S₀ Rydberg states of natural strontium in the range 10 ≤ n ≤ 70. While the isotope shifts between the even isotopes 84, 86, and 88 showed no change, a dramatic increase of the shift with increasing principal quantum number was found for the odd isotope Sr-87.     

Nuclear moments and charge radii of107–111in determined by laser spectroscopy

Collinear fast beam laser spectroscopy has been used to measure the hyperfine structure and isotope shift in the atomic 5s ² 5p ² P _3/2-5s ² 6s ² S _1/2 transition (λ=451 nm) of^107–111In. Secondary beams of neutron deficient indium isotopes were prepared at the GSI on-line mass separator following fusion evaporation reactions. Magnetic dipole moments and electric quadrupole moments have been determined. The isotope shifts are discussed in terms of the change of the mean square nuclear charge radii and compared with the droplet model predictions and the deformation values calculated from the quadrupole moments.     

PRECISE MEASUREMENT OF DENSITY-DEPENDENT SHIFT BY WAVELENGTH MODULATION REFLECTION SPECTROSCOPY

The density dependence of the line shift of the cesium D₂ line is studied with sub-Doppler selective reflection spectroscopy. By use of wavelength modulation and sixth-harmonics detection we observed the coefficient of the pressure-induced shift of the 6S_1/2(F=4)→6P_3/2(F'=3) hyperfine transition of the cesium D₂ line Δδ/ρ=-0.9(5)×10^-8cm³. In the limit ρ=0 a frequency shift about -3MHz remains, which may be attributed to long-range atom－surface interactions. The experimental results can be used in measurements of the local field-induced frequency shift at high atomic densities with sufficient accuracy.     

Analysis of the isotope shifts and hyperfine structure in the 3 988 Å (6s6p 1 P 1↔6s 2 1 S 0) YbI line

High-resolution laser spectroscopy using a pulsed dye-laser acting on a collimated atomic beam has been used to determine the isotope shifts in the 3 988 Å YbI line. The following results have been obtained:Δσ(176, 174)=?509(4)MHz,Δσ (174, 173)=?291(10) MHz,Δσ(174, 172)=?530(4) MHz,Δσ(172, 171)=?414(5) MHz andΔσ(172, 170)= ?665(10) MHz. The sign of the magnetic dipole interaction constant in the¹ P ₁ state for¹⁷¹Yb is found to be negative,a(¹ P ₁, 171)=?213.4(3.0) MHz. The electric quadrupole interaction constant for¹⁷³Yb in the¹ P ₁ state is found to beb(¹ P ₁, 173)=605(20) MHz.     

Laser spectroscopy of stable Os isotopes

Doppler-free isotope shift measurements of the stable even ^184–192Os and ^187,189Os odd isotopes have been performed for the first time on the 5d ⁶6s ^{2 5}D₄→5d ⁶6s6p ⁷F₄ (305.9 nm) transition in the neutral atom by atomic beam laser spectroscopy and on the ionic 5d ⁶6s ⁵D_9/2→5d ⁶6p ⁶D_7/2 (228.2 nm) transition by fast collinear ion-laser spectroscopy. The measurements were carried out in Manchester and at the IGISOL facility in Jyväskylä in Finland, respectively. The results presented are the most precise measurements to-date of the absolute isotope shifts.     

Magneto-optical trapping of bosonic and fermionic neon isotopes and their mixtures: isotope shift of the 3P2 ↔ 3D3 transition and hyperfine constants of the 3D3 state of 21Ne

We have magneto-optically trapped all three stable neon isotopes, including the rare ²¹Ne, and all two-isotope combinations. The atoms are prepared in the metastable ³P₂ state and manipulated via laser interaction on the ³P₂ ? ³D₃ transition at 640.2?nm. These cold (T ≈ 1?mK) and environmentally decoupled atom samples present ideal objects for precision measurements and the investigation of interactions between cold and ultracold metastable atoms. In this work, we present accurate measurements of the isotope shift of the ³P₂ ? ³D₃ transition and the hyperfine interaction constants of the ³D₃ state of ²¹Ne. The determined isotope shifts are (1625.9 ± 0.15)?MHz for ²⁰Ne ? ²²Ne, (855.7 ± 1.0)?MHz for ²⁰Ne ? ²¹Ne, and (770.3 ± 1.0)?MHz for ²¹Ne ? ²²Ne. The obtained magnetic dipole and electric quadrupole hyperfine interaction constants are A(³D₃) = (?142.4 ± 0.2)?MHz and B(³D₃) = (?107.7 ± 1.1)?MHz, respectively. All measurements give a reduction of uncertainty by about one order of magnitude over previous measurements.