Physical Review A

Measurement of the lifetime of a metastable excited state in Bi−

Moa K. Kristiansson, Julia Karls, N. D. Gibson, D. Hanstorp, Henning T. Schmidt, C. W. Walter

Published Jan 18, 2022• 2 citations

Abstract

The lifetime of the $^{3}P_{0}$ state of ${\mathrm{Bi}}^{\ensuremath{-}}$ has been measured by selective photodetachment in a cryogenic ion-beam storage ring. By measuring the lifetime as a function of applied laser powers and extrapolating to zero laser power, a lifetime of $16.0\ifmmode\pm\else\textpm\fi{}0.5$ s is deduced for electric quadrupole decay of the excited state to the ground sate. The result provides a stringent test of recent state-of-the art theoretical calculations.

DOI: 10.1103/physreva.105.l010801

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Physical Review A

Measurement of the lifetime of a metastable excited state in Bi−

Moa K. Kristiansson, Julia Karls, N. D. Gibson, D. Hanstorp, Henning T. Schmidt, C. W. Walter

Published Jan 18, 2022• 2 citations

Publisher

Abstract

The lifetime of the

^{3}P_{0}

state of

{\mathrm{Bi}}^{\ensuremath{-}}

has been measured by selective photodetachment in a cryogenic ion-beam storage ring. By measuring the lifetime as a function of applied laser powers and extrapolating to zero laser power, a lifetime of

16.0\ifmmode\pm\else\textpm\fi{}0.5

s is deduced for electric quadrupole decay of the excited state to the ground sate. The result provides a stringent test of recent state-of-the art theoretical calculations.

DOI: 10.1103/physreva.105.l010801

Related papers

Metastable-ion lifetime studies utilizing a heavy-ion storage ring: Measurements on He−

T. Andersen, L. H. Andersen, Péter Balling +4 more

The lifetime of the metastable autodetaching 1s2s2p $^{4}$ ${\mathit{P}}_{5/2}$ level of the $^{4}\mathrm{He}^{\mathrm{\ensuremath{-}}}$ ion has been measured by a time-of-flight technique to be 350\ifmmode\pm\else\textpm\fi{}15 \ensuremath{\mu}s using a heavy-ion storage ring. Blackbody-induced photodetachment of this weakly bound level is shown to influence the decay rate by nearly 20%, an effect not discussed previously. The magnetic-field-induced mixing effects provide additional information about the lifetime of the close-lying $^{4}$ ${\mathit{P}}_{3/2}$ level, yielding \ensuremath{\tau} ${(}^{4}$ ${\mathit{P}}_{3/2}$ )=12\ifmmode\pm\else\textpm\fi{}2 \ensuremath{\mu}s. The observed lifetimes are consistent with previous experimental values, but the accuracy of the $^{4}$ ${\mathit{P}}_{5/2}$ lifetime is improved by a factor of 6, allowing a detailed test of theoretical predictions to be performed. The $^{4}$ ${\mathit{P}}_{5/2}$ lifetime is significantly shorter than most recent advanced theoretical results, but in agreement with a multiconfiguration Hartree-Fock approach accurately describing the initial bound $^{4}$ ${\mathit{P}}_{5/2}$ and the final continuum $^{2}$ ${\mathit{F}}_{5/2}$ states.The lifetime of the metastable autodetaching 1s2s2p $^{4}$${\mathit{P}}_{5/2}$ level of the $^{4}\mathrm{He}^{\mathrm{\ensuremath{-}}}$ ion has been measured by a time-of-flight technique to be 350\ifmmode\pm\else\textpm\fi{}15 \ensuremath{\mu}s using a heavy-ion storage ring. Blackbody-induced photodetachment of this weakly bound level is shown to influence the decay rate by nearly 20%, an effect not discussed previously. The magnetic-field-induced mixing effects provide additional information about the lifetime of the close-lying $^{4}$${\mathit{P}}_{3/2}$ level, yielding \ensuremath{\tau}${(}^{4}$${\mathit{P}}_{3/2}$)=12\ifmmode\pm\else\textpm\fi{}2 \ensuremath{\mu}s. The observed lifetimes are consistent with previous experimental values, but the accuracy of the $^{4}$${\mathit{P}}_{5/2}$ lifetime is improved by a factor of 6, allowing a detailed test of theoretical predictions to be performed. The $^{4}$${\mathit{P}}_{5/2}$ lifetime is significantly shorter than most recent advanced theoretical results, but in agreement with a multiconfiguration Hartree-Fock approach accurately describing the initial bound $^{4}$${\mathit{P}}_{5/2}$ and the final continuum $^{2}$${\mathit{F}}_{5/2}$ states.

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The negative ion of lanthanum has one of the richest bound-state spectra observed for an atomic negative ion and it has been proposed as a promising candidate for laser cooling, which has not yet been achieved for any negatively charged system. In the present study, radiative decays of low-lying excited states of ${\mathrm{La}}^{\ensuremath{-}}$ were experimentally investigated at the DESIREE cryogenic electrostatic ion-beam storage ring facility using state-selective photodetachment over storage times of up to 800 s. Independently, the transition rates for the relevant states were calculated using a high-precision hybrid theoretical approach. The measured lifetime of the lowest excited state of ${\mathrm{La}}^{\ensuremath{-}}$ $({}^{3}{F}_{3}^{e})$ of 132(20) s agrees very well with the theoretical calculations and previous predictions. However, a puzzling discrepancy exists for the next-higher state ${}^{3}{F}_{4}^{e}$ , with the experiments yielding a lifetime $\ensuremath{\sim}4$ times shorter than calculated, highlighting the challenges for this complex ion. The results provide valuable insights into the prospects for laser cooling ${\mathrm{La}}^{\ensuremath{-}}$.The negative ion of lanthanum has one of the richest bound-state spectra observed for an atomic negative ion and it has been proposed as a promising candidate for laser cooling, which has not yet been achieved for any negatively charged system. In the present study, radiative decays of low-lying excited states of ${\mathrm{La}}^{\ensuremath{-}}$ were experimentally investigated at the DESIREE cryogenic electrostatic ion-beam storage ring facility using state-selective photodetachment over storage times of up to 800 s. Independently, the transition rates for the relevant states were calculated using a high-precision hybrid theoretical approach. The measured lifetime of the lowest excited state of ${\mathrm{La}}^{\ensuremath{-}}$ $({}^{3}{F}_{3}^{e})$ of 132(20) s agrees very well with the theoretical calculations and previous predictions. However, a puzzling discrepancy exists for the next-higher state ${}^{3}{F}_{4}^{e}$, with the experiments yielding a lifetime $\ensuremath{\sim}4$ times shorter than calculated, highlighting the challenges for this complex ion. The results provide valuable insights into the prospects for laser cooling ${\mathrm{La}}^{\ensuremath{-}}$.

Physical Review AOct 3, 20250 citations

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Synopsis Anions of iridium were stored in the cryogenic storage ring, DESIREE [1, 2, 3] and investigated using laser photodetachment. The ions were stored for up to 2000 seconds and the relaxation of several metastable states were studied by selecting different photon energies. The threshold of the previously not observed 3P2 level is located and the lifetime of this sate is found to be longer than the storage time of the ion beam. We also find that a state exists higher in energy than the previously known level with a lifetime in the range of hundreds of milliseconds.Synopsis Anions of iridium were stored in the cryogenic storage ring, DESIREE [1, 2, 3] and investigated using laser photodetachment. The ions were stored for up to 2000 seconds and the relaxation of several metastable states were studied by selecting different photon energies. The threshold of the previously not observed 3P2 level is located and the lifetime of this sate is found to be longer than the storage time of the ion beam. We also find that a state exists higher in energy than the previously known level with a lifetime in the range of hundreds of milliseconds.

Journal of Physics Conference SeriesJan 1, 20200 citations

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Xiaotong Lu, Feng Guo, Yanyan Liu +6 more

We report a measurement of the radiative lifetime of the $5s5p\phantom{\rule{0.25em}{0ex}}{}^{3}{P}_{0}^{\mathrm{o}}$ metastable state in ${}^{87}\mathrm{Sr}$ , which is coupled to the $5{s}^{2}\phantom{\rule{0.25em}{0ex}}\phantom{\rule{0.2em}{0ex}}{}^{1}{S}_{0}$ ground state via a hyperfine-induced electric dipole transition. The radiative lifetime is determined to be 151.4(48) s, in good agreement with theoretical results. Our approach relies on accurate measurements of laser intensity and free-space Rabi frequency, enabling lifetime measurements of any excited state and particularly suitable for long-lived states.We report a measurement of the radiative lifetime of the $5s5p\phantom{\rule{0.25em}{0ex}}{}^{3}{P}_{0}^{\mathrm{o}}$ metastable state in ${}^{87}\mathrm{Sr}$, which is coupled to the $5{s}^{2}\phantom{\rule{0.25em}{0ex}}\phantom{\rule{0.2em}{0ex}}{}^{1}{S}_{0}$ ground state via a hyperfine-induced electric dipole transition. The radiative lifetime is determined to be 151.4(48) s, in good agreement with theoretical results. Our approach relies on accurate measurements of laser intensity and free-space Rabi frequency, enabling lifetime measurements of any excited state and particularly suitable for long-lived states.

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The natural lifetime of the metastable $4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ state in $^{88}\mathrm{Sr}^{+}$ has been measured using a single laser-cooled, trapped ion. The ion was prepared in the $4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ state by laser excitation of the $5s\phantom{\rule{0.2em}{0ex}}^{2}S_{1∕2}\ensuremath{-}4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ quadrupole transition at 674 nm. The decay time was measured by using Dehmelt's electron shelving method to monitor the ion's electronic state. Two separate investigations were conducted under slightly different experimental conditions. 160 000 decay times from the $4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ state were observed in total, and two different methods for determining the statistical value of the measured lifetime have been compared. Systematic effects have also been estimated, and including these effects yields a value of $\ensuremath{\tau}=390.8(1.6)\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$ ($1\ensuremath{\sigma}$ uncertainty) for the natural lifetime.The natural lifetime of the metastable $4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ state in $^{88}\mathrm{Sr}^{+}$ has been measured using a single laser-cooled, trapped ion. The ion was prepared in the $4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ state by laser excitation of the $5s\phantom{\rule{0.2em}{0ex}}^{2}S_{1∕2}\ensuremath{-}4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ quadrupole transition at 674 nm. The decay time was measured by using Dehmelt's electron shelving method to monitor the ion's electronic state. Two separate investigations were conducted under slightly different experimental conditions. 160 000 decay times from the $4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ state were observed in total, and two different methods for determining the statistical value of the measured lifetime have been compared. Systematic effects have also been estimated, and including these effects yields a value of $\ensuremath{\tau}=390.8(1.6)\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$ ($1\ensuremath{\sigma}$ uncertainty) for the natural lifetime.

Physical Review AJul 13, 200539 citations

Lifetime Measurement of the Metastable 4dD3/22 Level in Sr+ by Optical Pumping of a Stored Ion Beam

S. Mannervik, Johan Lidberg, L.‐O. Norlin +4 more

Optical pumping has been applied to a stored ion beam of singly charged strontium. Collinear laser excitation in the storage ring transferred the main part of the ion beam into the metastable $4d^{2}D_{3/2}$ level. Subsequent observation of the forbidden electric quadrupole transition to the ground state yielded information about the radiative lifetime of the metastable state. With this new method a lifetime of $435\ifmmode\pm\else\textpm\fi{}4\mathrm{ms}$ was obtained. The metastable $4d^{2}D$ levels are presently focused on as candidates for a new frequency standard.Optical pumping has been applied to a stored ion beam of singly charged strontium. Collinear laser excitation in the storage ring transferred the main part of the ion beam into the metastable $4d^{2}D_{3/2}$ level. Subsequent observation of the forbidden electric quadrupole transition to the ground state yielded information about the radiative lifetime of the metastable state. With this new method a lifetime of $435\ifmmode\pm\else\textpm\fi{}4\mathrm{ms}$ was obtained. The metastable $4d^{2}D$ levels are presently focused on as candidates for a new frequency standard.

Physical Review LettersJul 26, 199932 citations

The lifetime of the

^{3}P_{0}

state of

{\mathrm{Bi}}^{\ensuremath{-}}

16.0\ifmmode\pm\else\textpm\fi{}0.5

s is deduced for electric quadrupole decay of the excited state to the ground sate. The result provides a stringent test of recent state-of-the art theoretical calculations.

The lifetime of the metastable autodetaching 1s2s2p

^{4}

{\mathit{P}}_{5/2}

level of the $^{4}\mathrm{He}^{\mathrm{\ensuremath{-}}}$ ion has been measured by a time-of-flight technique to be 350\ifmmode\pm\else\textpm\fi{}15 \ensuremath{\mu}s using a heavy-ion storage ring. Blackbody-induced photodetachment of this weakly bound level is shown to influence the decay rate by nearly 20%, an effect not discussed previously. The magnetic-field-induced mixing effects provide additional information about the lifetime of the close-lying

^{4}

{\mathit{P}}_{3/2}

level, yielding \ensuremath{\tau}

{(}^{4}

{\mathit{P}}_{3/2}

)=12\ifmmode\pm\else\textpm\fi{}2 \ensuremath{\mu}s. The observed lifetimes are consistent with previous experimental values, but the accuracy of the

^{4}

{\mathit{P}}_{5/2}

lifetime is improved by a factor of 6, allowing a detailed test of theoretical predictions to be performed. The

^{4}

{\mathit{P}}_{5/2}

lifetime is significantly shorter than most recent advanced theoretical results, but in agreement with a multiconfiguration Hartree-Fock approach accurately describing the initial bound

^{4}

{\mathit{P}}_{5/2}

and the final continuum

^{2}

{\mathit{F}}_{5/2}

states.

({}^{3}{F}_{3}^{e})

of 132(20) s agrees very well with the theoretical calculations and previous predictions. However, a puzzling discrepancy exists for the next-higher state

{}^{3}{F}_{4}^{e}

, with the experiments yielding a lifetime $\ensuremath{\sim}4$ times shorter than calculated, highlighting the challenges for this complex ion. The results provide valuable insights into the prospects for laser cooling ${\mathrm{La}}^{\ensuremath{-}}$.

We report a measurement of the radiative lifetime of the

5s5p\phantom{\rule{0.25em}{0ex}}{}^{3}{P}_{0}^{\mathrm{o}}

metastable state in

{}^{87}\mathrm{Sr}

, which is coupled to the

5{s}^{2}\phantom{\rule{0.25em}{0ex}}\phantom{\rule{0.2em}{0ex}}{}^{1}{S}_{0}

ground state via a hyperfine-induced electric dipole transition. The radiative lifetime is determined to be 151.4(48) s, in good agreement with theoretical results. Our approach relies on accurate measurements of laser intensity and free-space Rabi frequency, enabling lifetime measurements of any excited state and particularly suitable for long-lived states.

The natural lifetime of the metastable

4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}

state in

^{88}\mathrm{Sr}^{+}

has been measured using a single laser-cooled, trapped ion. The ion was prepared in the

4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}

state by laser excitation of the $5s\phantom{\rule{0.2em}{0ex}}^{2}S_{1∕2}\ensuremath{-}4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ quadrupole transition at 674 nm. The decay time was measured by using Dehmelt's electron shelving method to monitor the ion's electronic state. Two separate investigations were conducted under slightly different experimental conditions. 160 000 decay times from the

4d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}

state were observed in total, and two different methods for determining the statistical value of the measured lifetime have been compared. Systematic effects have also been estimated, and including these effects yields a value of $\ensuremath{\tau}=390.8(1.6)\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$ ($1\ensuremath{\sigma}$ uncertainty) for the natural lifetime.

Optical pumping has been applied to a stored ion beam of singly charged strontium. Collinear laser excitation in the storage ring transferred the main part of the ion beam into the metastable

4d^{2}D_{3/2}

level. Subsequent observation of the forbidden electric quadrupole transition to the ground state yielded information about the radiative lifetime of the metastable state. With this new method a lifetime of $435\ifmmode\pm\else\textpm\fi{}4\mathrm{ms}$ was obtained. The metastable

4d^{2}D

levels are presently focused on as candidates for a new frequency standard.