Physical Review A

Disentanglement of magnetic field mixing reveals the spontaneous M2 decay rate for a metastable level in Xe+

Peter Schef, Peter Lundin, Émile Biémont, A. Källberg, L.‐O. Norlin, P. Palmeri, Peder Royen, A. Simonsson, S. Mannervik

Published Aug 3, 2005• 9 citations

Publisher

Abstract

We have investigated the radiative decay of the metastable level $5d^{4}D_{7∕2}$ in ${\mathrm{Xe}}^{+}$. Theoretically we find the decay to be heavily dominated by an $M2$ transition and not by $M1∕E2$ transitions. Lifetime measurements of $5d^{4}D_{7∕2}$ in a storage ring are difficult since magnetic mixing of the metastable with a short-lived level quenches its population. Decay rates were determined at different magnetic field strengths $(B)$ in order to allow a nonlinear extrapolation to $B=0$. The experimental lifetime of $2.4\ifmmode\pm\else\textpm\fi{}0.8\phantom{\rule{0.3em}{0ex}}\mathrm{s}$ was in agreement with the calculated value, but much smaller than previously estimated.

DOI: 10.1103/physreva.72.020501

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Lifetime measurement of He− using an electrostatic ion trap

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Direct measurement of the metastable 3P2 decay rate in krypton

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Lifetime determination of the 5d2 3F2 state in barium using trapped atoms

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arXiv:1502.07855Physical Review AMar 26, 20151 citation

Physical Review A

Disentanglement of magnetic field mixing reveals the spontaneous M2 decay rate for a metastable level in Xe+

Peter Schef, Peter Lundin, Émile Biémont, A. Källberg, L.‐O. Norlin, P. Palmeri, Peder Royen, A. Simonsson, S. Mannervik

Published Aug 3, 2005• 9 citations

Publisher

Abstract

We have investigated the radiative decay of the metastable level

5d^{4}D_{7∕2}

{\mathrm{Xe}}^{+}

. Theoretically we find the decay to be heavily dominated by an

M2

transition and not by

M1∕E2

transitions. Lifetime measurements of

5d^{4}D_{7∕2}

in a storage ring are difficult since magnetic mixing of the metastable with a short-lived level quenches its population. Decay rates were determined at different magnetic field strengths

(B)

in order to allow a nonlinear extrapolation to

B=0

. The experimental lifetime of

2.4\ifmmode\pm\else\textpm\fi{}0.8\phantom{\rule{0.3em}{0ex}}\mathrm{s}

was in agreement with the calculated value, but much smaller than previously estimated.

DOI: 10.1103/physreva.72.020501

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.

Physical Review AFeb 1, 199377 citations

Radiative lifetime of metastable Xe3+ measured using an electrostatic ion beam trap

M. Saito, Asahi Chikaoka, T. Majima +2 more

Journal of Physics Conference SeriesJul 1, 20170 citations

Strong Hyperfine Induced Quenching of a Metastable State in Xe+ Observed by Hyperfine Selective Laser Probing of a Stored Ion Beam

S. Mannervik, Lars Broström, Johan Lidberg +2 more

A hyperfine state selective laser probing technique is presented to be used for lifetime determination of metastable states in an ion storage ring. Evidence for a drastic difference between the decay rates of the hyperfine states of the metastable level $5d{}^{4}{D}_{7/2}$ in ${}^{129}{\mathrm{Xe}}^{+}$ has been obtained by this method.A hyperfine state selective laser probing technique is presented to be used for lifetime determination of metastable states in an ion storage ring. Evidence for a drastic difference between the decay rates of the hyperfine states of the metastable level $5d{}^{4}{D}_{7/2}$ in ${}^{129}{\mathrm{Xe}}^{+}$ has been obtained by this method.

Physical Review LettersMay 13, 199635 citations

Lifetime measurement of He− using an electrostatic ion trap

Alex Wolf, K. G. Bhushan, I. Ben-Itzhak +4 more

The lifetimes of the metastable $1s2s2p{ }^{4}{P}_{5/2}$ level of ${\mathrm{He}}^{\ensuremath{-}},$ as well as the lifetime of the average of the ${}^{4}{P}_{3/2}$ and ${}^{4}{P}_{1/2}$ levels, have been measured using a new type of ion trap that stores keV ion beams using electrostatic fields only. The use of a pure electrostatic field avoids the complication of magnetic-field-induced mixing effects, which can interfere with the measurement of the spontaneous decay. The measured lifetime for the ${}^{4}{P}_{5/2}$ state, after correction for decay induced by blackbody radiation, is $343\ifmmode\pm\else\textpm\fi{}10 \ensuremath{\mu}\mathrm{s}.$ This value is consistent with previous experiments, and in excellent agreement with the most recent theoretical calculations. The average lifetime of the ${}^{4}{P}_{3/2}$ and ${}^{4}{P}_{1/2}$ is $8.9\ifmmode\pm\else\textpm\fi{}0.2 \ensuremath{\mu}\mathrm{s},$ which is about 20% lower than the weighted theoretical value.The lifetimes of the metastable $1s2s2p{ }^{4}{P}_{5/2}$ level of ${\mathrm{He}}^{\ensuremath{-}},$ as well as the lifetime of the average of the ${}^{4}{P}_{3/2}$ and ${}^{4}{P}_{1/2}$ levels, have been measured using a new type of ion trap that stores keV ion beams using electrostatic fields only. The use of a pure electrostatic field avoids the complication of magnetic-field-induced mixing effects, which can interfere with the measurement of the spontaneous decay. The measured lifetime for the ${}^{4}{P}_{5/2}$ state, after correction for decay induced by blackbody radiation, is $343\ifmmode\pm\else\textpm\fi{}10 \ensuremath{\mu}\mathrm{s}.$ This value is consistent with previous experiments, and in excellent agreement with the most recent theoretical calculations. The average lifetime of the ${}^{4}{P}_{3/2}$ and ${}^{4}{P}_{1/2}$ is $8.9\ifmmode\pm\else\textpm\fi{}0.2 \ensuremath{\mu}\mathrm{s},$ which is about 20% lower than the weighted theoretical value.

Physical Review AJan 1, 199956 citations

Direct measurement of the metastable 3P2 decay rate in krypton

J. Lefers, N. Miller, David S. N. Rupke +2 more

We use a magneto-optical trap to isolate ${}^{84}\mathrm{Kr}$ atoms in the metastable ${}^{3}{P}_{2}$ state and then measure the rate of 125.0-nm fluorescence due to spontaneous magnetic quadrupole $(M2)$ decay. We normalize the overall fluorescence rate from the sample using a ``quenching'' process in which laser excitation provides a path for prompt decay to the ground state, with each atom emitting one 123.6-nm photon. A single, solar-blind photomultiplier tube is used to detect both the $M2$ and the quench-induced photons, so that only small corrections relating to spectral response are necessary. We find a spontaneous decay rate of $\ensuremath{\Gamma}=0.0354(22){\mathrm{s}}^{\ensuremath{-}1},$ which translates into a lifetime of 28.3(1.8) s. This result is discussed in the context of previous measurements and calculations of ${}^{3}{P}_{2}$ lifetimes in the rare gases.We use a magneto-optical trap to isolate ${}^{84}\mathrm{Kr}$ atoms in the metastable ${}^{3}{P}_{2}$ state and then measure the rate of 125.0-nm fluorescence due to spontaneous magnetic quadrupole $(M2)$ decay. We normalize the overall fluorescence rate from the sample using a ``quenching'' process in which laser excitation provides a path for prompt decay to the ground state, with each atom emitting one 123.6-nm photon. A single, solar-blind photomultiplier tube is used to detect both the $M2$ and the quench-induced photons, so that only small corrections relating to spectral response are necessary. We find a spontaneous decay rate of $\ensuremath{\Gamma}=0.0354(22){\mathrm{s}}^{\ensuremath{-}1},$ which translates into a lifetime of 28.3(1.8) s. This result is discussed in the context of previous measurements and calculations of ${}^{3}{P}_{2}$ lifetimes in the rare gases.

Physical Review AJul 30, 200218 citations

Lifetime determination of the 5d2 3F2 state in barium using trapped atoms

Subhadeep De, Umakanth Dammalapati, Lorenz Willmann

Magneto-optically trapped atoms enable the determination of lifetimes of metastable states and higher lying excited states like the $5{d}^{2}{\phantom{\rule{0.28em}{0ex}}}^{3}{F}_{2}$ state in barium. The state is efficiently populated by driving strong transitions from metastable states within the cooling cycle of the barium magneto-optical trap (MOT). The lifetime is inferred from the increase of MOT fluorescence after the transfer of up to $30%$ of the trapped atoms to this state. The radiative decay of the $5{d}^{2}{\phantom{\rule{0.28em}{0ex}}}^{3}{F}_{2}$ state cascades to the cooling cycle of the MOT with a probability of $96.0(7)%$ corresponding to a trap loss of $4.0(7)%$ and its lifetime is determined to $160(10)\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{s}$. This is in good agreement with the theoretically calculated lifetime of $190\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{s}$ [V. A. Dzuba and V. V. Flambaum, J. Phys. B 40, 227 (2007)]. The determined loss of $4.0(7)%$ from the cooling cycle is compared with the theoretically calculated branching ratios. This measurement extends the efficacy of trapped atoms to measure lifetimes of higher, long-lived states and validate the atomic structure calculations of heavy multielectron systems.Magneto-optically trapped atoms enable the determination of lifetimes of metastable states and higher lying excited states like the $5{d}^{2}{\phantom{\rule{0.28em}{0ex}}}^{3}{F}_{2}$ state in barium. The state is efficiently populated by driving strong transitions from metastable states within the cooling cycle of the barium magneto-optical trap (MOT). The lifetime is inferred from the increase of MOT fluorescence after the transfer of up to $30%$ of the trapped atoms to this state. The radiative decay of the $5{d}^{2}{\phantom{\rule{0.28em}{0ex}}}^{3}{F}_{2}$ state cascades to the cooling cycle of the MOT with a probability of $96.0(7)%$ corresponding to a trap loss of $4.0(7)%$ and its lifetime is determined to $160(10)\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{s}$. This is in good agreement with the theoretically calculated lifetime of $190\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{s}$ [V. A. Dzuba and V. V. Flambaum, J. Phys. B 40, 227 (2007)]. The determined loss of $4.0(7)%$ from the cooling cycle is compared with the theoretically calculated branching ratios. This measurement extends the efficacy of trapped atoms to measure lifetimes of higher, long-lived states and validate the atomic structure calculations of heavy multielectron systems.

arXiv:1502.07855Physical Review AMar 26, 20151 citation

We have investigated the radiative decay of the metastable level

5d^{4}D_{7∕2}

{\mathrm{Xe}}^{+}

. Theoretically we find the decay to be heavily dominated by an

M2

transition and not by

M1∕E2

transitions. Lifetime measurements of

5d^{4}D_{7∕2}

in a storage ring are difficult since magnetic mixing of the metastable with a short-lived level quenches its population. Decay rates were determined at different magnetic field strengths

(B)

in order to allow a nonlinear extrapolation to

B=0

. The experimental lifetime of

2.4\ifmmode\pm\else\textpm\fi{}0.8\phantom{\rule{0.3em}{0ex}}\mathrm{s}

was in agreement with the calculated value, but much smaller than previously estimated.

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.

5d{}^{4}{D}_{7/2}

{}^{129}{\mathrm{Xe}}^{+}

has been obtained by this method.

The lifetimes of the metastable

1s2s2p{ }^{4}{P}_{5/2}

level of ${\mathrm{He}}^{\ensuremath{-}},$ as well as the lifetime of the average of the

{}^{4}{P}_{3/2}

and

{}^{4}{P}_{1/2}

levels, have been measured using a new type of ion trap that stores keV ion beams using electrostatic fields only. The use of a pure electrostatic field avoids the complication of magnetic-field-induced mixing effects, which can interfere with the measurement of the spontaneous decay. The measured lifetime for the

{}^{4}{P}_{5/2}

state, after correction for decay induced by blackbody radiation, is $343\ifmmode\pm\else\textpm\fi{}10 \ensuremath{\mu}\mathrm{s}.$ This value is consistent with previous experiments, and in excellent agreement with the most recent theoretical calculations. The average lifetime of the

{}^{4}{P}_{3/2}

and

{}^{4}{P}_{1/2}

is $8.9\ifmmode\pm\else\textpm\fi{}0.2 \ensuremath{\mu}\mathrm{s},$ which is about 20% lower than the weighted theoretical value.

We use a magneto-optical trap to isolate

{}^{84}\mathrm{Kr}

atoms in the metastable

{}^{3}{P}_{2}

state and then measure the rate of 125.0-nm fluorescence due to spontaneous magnetic quadrupole

(M2)

decay. We normalize the overall fluorescence rate from the sample using a ``quenching'' process in which laser excitation provides a path for prompt decay to the ground state, with each atom emitting one 123.6-nm photon. A single, solar-blind photomultiplier tube is used to detect both the

M2

and the quench-induced photons, so that only small corrections relating to spectral response are necessary. We find a spontaneous decay rate of $\ensuremath{\Gamma}=0.0354(22){\mathrm{s}}^{\ensuremath{-}1},$ which translates into a lifetime of 28.3(1.8) s. This result is discussed in the context of previous measurements and calculations of

{}^{3}{P}_{2}

lifetimes in the rare gases.

Magneto-optically trapped atoms enable the determination of lifetimes of metastable states and higher lying excited states like the

5{d}^{2}{\phantom{\rule{0.28em}{0ex}}}^{3}{F}_{2}

state in barium. The state is efficiently populated by driving strong transitions from metastable states within the cooling cycle of the barium magneto-optical trap (MOT). The lifetime is inferred from the increase of MOT fluorescence after the transfer of up to

30%

of the trapped atoms to this state. The radiative decay of the

5{d}^{2}{\phantom{\rule{0.28em}{0ex}}}^{3}{F}_{2}

state cascades to the cooling cycle of the MOT with a probability of

96.0(7)%

corresponding to a trap loss of

4.0(7)%

and its lifetime is determined to $160(10)\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{s}$. This is in good agreement with the theoretically calculated lifetime of $190\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{s}$ [V. A. Dzuba and V. V. Flambaum, J. Phys. B 40, 227 (2007)]. The determined loss of

4.0(7)%

from the cooling cycle is compared with the theoretically calculated branching ratios. This measurement extends the efficacy of trapped atoms to measure lifetimes of higher, long-lived states and validate the atomic structure calculations of heavy multielectron systems.