Physical Review A

Observation of the F3 metastable states of neutral barium

Stephen G. Schmelling, Gilbert O. Brink

Published Dec 1, 1975• 9 citations

Abstract

The $^{3}F$ metastable states of the $5{d}^{2}$ configuration of neutral barium have been observed in an atomic beam. As far as can be determined from the literature, these states have not been observed previously. Their $g$ factors have been measured, and the transmission characteristics of the apparatus indicate a lifetime of at least ${10}^{\ensuremath{-}3}$ sec.

DOI: 10.1103/physreva.12.2498

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g Factors of the 6s5d Configuration of Atomic Barium

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Measurement of the lifetime of the 5d6pF31 state of barium

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

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Observation of Circular-Metastable Doubly Excited States of Barium

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Physical Review A

Observation of the F3 metastable states of neutral barium

Stephen G. Schmelling, Gilbert O. Brink

Published Dec 1, 1975• 9 citations

Publisher

Abstract

The

^{3}F

metastable states of the

5{d}^{2}

configuration of neutral barium have been observed in an atomic beam. As far as can be determined from the literature, these states have not been observed previously. Their

g

factors have been measured, and the transmission characteristics of the apparatus indicate a lifetime of at least

{10}^{\ensuremath{-}3}

sec.

DOI: 10.1103/physreva.12.2498

Related papers

g Factors of the 6s5d Configuration of Atomic Barium

Gilbert O. Brink, Robert J. Hull

The four metastable states of atomic barium comprising the $6s5d$ configuration have been studied by atomic-beam magnetic resonance, and information concerning their $g$ factors has been obtained. Data from this work agree with that obtained recently by v. Oppen using a different method, and agreement is also obtained with theory.The four metastable states of atomic barium comprising the $6s5d$ configuration have been studied by atomic-beam magnetic resonance, and information concerning their $g$ factors has been obtained. Data from this work agree with that obtained recently by v. Oppen using a different method, and agreement is also obtained with theory.

Physical ReviewMar 5, 19695 citations

Measurement of the lifetime of the 5d6pF31 state of barium

Paul E. Jessop, F. M. Pipkin

A delayed-coincidence technique has been used to measure the lifetime of the $5d6p^{1}F_{3}$ state of atomic barium. An intermediate, $6s5d^{1}D_{2}$ metastable state of barium atoms in an atomic beam was populated by electron bombardment, and a pulsed cw laser was employed to excite atoms from the metastable state to the $5d6p^{1}F_{3}$ state. A time-to-amplitude convertor was used to measure the time distribution of the fluorescent light. The value obtained for the lifetime was (44.5\ifmmode\pm\else\textpm\fi{}1.8) nsec.A delayed-coincidence technique has been used to measure the lifetime of the $5d6p^{1}F_{3}$ state of atomic barium. An intermediate, $6s5d^{1}D_{2}$ metastable state of barium atoms in an atomic beam was populated by electron bombardment, and a pulsed cw laser was employed to excite atoms from the metastable state to the $5d6p^{1}F_{3}$ state. A time-to-amplitude convertor was used to measure the time distribution of the fluorescent light. The value obtained for the lifetime was (44.5\ifmmode\pm\else\textpm\fi{}1.8) nsec.

Physical Review AJul 1, 19799 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

Auto-Ionizing States in the Alkali Atoms with Microsecond Lifetimes

P. D. Feldman, Robert Novick

Discrete atomic energy levels lying between the first and second ionization potentials which are metastable against both auto-ionization and radiative decay have been observed in the alkali elements. These levels arise from the excitation of an electron from the outermost closed shell of the atom and have characteristic lifetimes in the microsecond region. A beam of metastable alkali atoms is produced by electron bombardment of neutral ground-state atoms and is detected by collecting the charged products of the decay. Stern-Gerlach magnetic-deflection experiments have been performed to show unambiguously that the signals arise from paramagnetic atoms and not from possible stray-photon effects in the apparatus. The excitation energies, electron-bombardment production cross sections, natural lifetimes, and the tentative spectroscopic assignments of these atoms are listed below: The energy and lifetime of the metastable lithium atom are in good agreement with the available theoretical estimates. The metastable states in the heavier alkali atoms are classified in relation to the known ${\mathrm{I}}^{b}$ spectral terms. Magnetic and electric fields have been found to be effective in reducing the lifetime of the metastable atoms. The Zeeman quenching is discussed in a separate paper. The Stark quenching rate has been found to be proportional to the square of the electric field and to increase rapidly with atomic number $Z$ . It is suggested that the Stark quenching results from a second-order interaction which involves the product of the electric field and the spin-orbit or other magnetic operators.Discrete atomic energy levels lying between the first and second ionization potentials which are metastable against both auto-ionization and radiative decay have been observed in the alkali elements. These levels arise from the excitation of an electron from the outermost closed shell of the atom and have characteristic lifetimes in the microsecond region. A beam of metastable alkali atoms is produced by electron bombardment of neutral ground-state atoms and is detected by collecting the charged products of the decay. Stern-Gerlach magnetic-deflection experiments have been performed to show unambiguously that the signals arise from paramagnetic atoms and not from possible stray-photon effects in the apparatus. The excitation energies, electron-bombardment production cross sections, natural lifetimes, and the tentative spectroscopic assignments of these atoms are listed below: The energy and lifetime of the metastable lithium atom are in good agreement with the available theoretical estimates. The metastable states in the heavier alkali atoms are classified in relation to the known ${\mathrm{I}}^{b}$ spectral terms. Magnetic and electric fields have been found to be effective in reducing the lifetime of the metastable atoms. The Zeeman quenching is discussed in a separate paper. The Stark quenching rate has been found to be proportional to the square of the electric field and to increase rapidly with atomic number $Z$. It is suggested that the Stark quenching results from a second-order interaction which involves the product of the electric field and the spin-orbit or other magnetic operators.

Physical ReviewAug 5, 1967170 citations

Spectroscopy of barium atoms in liquid and solid helium matrices

Victor Lebedev, Peter Moroshkin, Antoine Weis

We present an exhaustive overview of optical absorption and laser-induced fluorescence lines of Ba atoms in liquid and solid helium matrices in visible and near-infrared spectral ranges. Due to the increased density of isolated atoms, we have found a large number of spectral lines that were not observed in condensed helium matrices before. We have also measured the lifetimes of metastable states. The lowest ${}^{3}{D}_{1}$ metastable state has lifetime of 2.6 s and can be used as an intermediate state in two-step excitations of high-lying states. Various matrix-induced radiationless population transfer channels have been identified.We present an exhaustive overview of optical absorption and laser-induced fluorescence lines of Ba atoms in liquid and solid helium matrices in visible and near-infrared spectral ranges. Due to the increased density of isolated atoms, we have found a large number of spectral lines that were not observed in condensed helium matrices before. We have also measured the lifetimes of metastable states. The lowest ${}^{3}{D}_{1}$ metastable state has lifetime of 2.6 s and can be used as an intermediate state in two-step excitations of high-lying states. Various matrix-induced radiationless population transfer channels have been identified.

Physical Review AAug 3, 201114 citations

Observation of Circular-Metastable Doubly Excited States of Barium

F. Roussel, M. Chéret, L. Chen +4 more

Using the adiabatic crossed-field method we have prepared for the first time doubly excited barium atoms with one valence electron in an oriented circular Rydberg state (n=21, l=m=20, denoted 21c) and the other electron in a ${6\mathrm{p}}_{\mathrm{j}}$ state. In a fraction of these atoms the inner electron decays radiatively to a ${5\mathrm{d}}_{\mathrm{j}\ensuremath{'}}$ metastable level. The obtained circular-metastable doubly excited atoms are very stable. For the (${5\mathrm{d}}_{3/2>}$21c) state the autoionization lifetime \ensuremath{\tau} is longer than 400 \ensuremath{\mu}s; for the (${5\mathrm{d}}_{5/2}$21c) state, \ensuremath{\tau}=1\ifmmode\pm\else\textpm\fi{}0.2 \ensuremath{\mu}s. the specific role of the 5d electron is demonstrated. \textcopyright{} 1990 The American Physical SocietyUsing the adiabatic crossed-field method we have prepared for the first time doubly excited barium atoms with one valence electron in an oriented circular Rydberg state (n=21, l=m=20, denoted 21c) and the other electron in a ${6\mathrm{p}}_{\mathrm{j}}$ state. In a fraction of these atoms the inner electron decays radiatively to a ${5\mathrm{d}}_{\mathrm{j}\ensuremath{'}}$ metastable level. The obtained circular-metastable doubly excited atoms are very stable. For the (${5\mathrm{d}}_{3/2>}$21c) state the autoionization lifetime \ensuremath{\tau} is longer than 400 \ensuremath{\mu}s; for the (${5\mathrm{d}}_{5/2}$21c) state, \ensuremath{\tau}=1\ifmmode\pm\else\textpm\fi{}0.2 \ensuremath{\mu}s. the specific role of the 5d electron is demonstrated. \textcopyright{} 1990 The American Physical Society

Physical Review LettersDec 17, 199020 citations

The

^{3}F

metastable states of the

5{d}^{2}

configuration of neutral barium have been observed in an atomic beam. As far as can be determined from the literature, these states have not been observed previously. Their

g

factors have been measured, and the transmission characteristics of the apparatus indicate a lifetime of at least

{10}^{\ensuremath{-}3}

sec.

The four metastable states of atomic barium comprising the

6s5d

configuration have been studied by atomic-beam magnetic resonance, and information concerning their

g

factors has been obtained. Data from this work agree with that obtained recently by v. Oppen using a different method, and agreement is also obtained with theory.

A delayed-coincidence technique has been used to measure the lifetime of the

5d6p^{1}F_{3}

state of atomic barium. An intermediate,

6s5d^{1}D_{2}

metastable state of barium atoms in an atomic beam was populated by electron bombardment, and a pulsed cw laser was employed to excite atoms from the metastable state to the

5d6p^{1}F_{3}

state. A time-to-amplitude convertor was used to measure the time distribution of the fluorescent light. The value obtained for the lifetime was (44.5\ifmmode\pm\else\textpm\fi{}1.8) nsec.

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.

{\mathrm{I}}^{b}

spectral terms. Magnetic and electric fields have been found to be effective in reducing the lifetime of the metastable atoms. The Zeeman quenching is discussed in a separate paper. The Stark quenching rate has been found to be proportional to the square of the electric field and to increase rapidly with atomic number

Z

. It is suggested that the Stark quenching results from a second-order interaction which involves the product of the electric field and the spin-orbit or other magnetic operators.

{}^{3}{D}_{1}

metastable state has lifetime of 2.6 s and can be used as an intermediate state in two-step excitations of high-lying states. Various matrix-induced radiationless population transfer channels have been identified.

{6\mathrm{p}}_{\mathrm{j}}

state. In a fraction of these atoms the inner electron decays radiatively to a ${5\mathrm{d}}_{\mathrm{j}\ensuremath{'}}$ metastable level. The obtained circular-metastable doubly excited atoms are very stable. For the (${5\mathrm{d}}_{3/2>}$21c) state the autoionization lifetime \ensuremath{\tau} is longer than 400 \ensuremath{\mu}s; for the (${5\mathrm{d}}_{5/2}$21c) state, \ensuremath{\tau}=1\ifmmode\pm\else\textpm\fi{}0.2 \ensuremath{\mu}s. the specific role of the 5d electron is demonstrated. \textcopyright{} 1990 The American Physical Society