Physical Review A

Determination of Energies and Lifetimes of the Metastable Auto-Ionizing (1s2s2p)P4 States of Li6 and Li7 by a Zeeman-Quenching Technique

M. Levitt, Robert Novick, P. D. Feldman

Published Jan 1, 1971• 58 citations

Abstract

A Zeeman-quenching atomic-beam method has been utilized for the determination of the fine- and hyperfine-structure energies and auto-ionization lifetimes of the metastable $(1s2s2p)^{4}P_{J}$ states of ${\mathrm{Li}}^{6}$ and ${\mathrm{Li}}^{7}$. Both the fine-structure intervals and the lifetimes of the $J=\frac{3}{2}$ and $J=\frac{1}{2}$ states are found to be in disagreement with existing theoretical calculations. The quenching of metastable lithium atoms in a nonuniform magnetic field can be satisfactorily described with the aid of the "adiabatic criterion." The present results also permit a quantitative evaluation of a proposal for producing polarized lithium nuclei.

DOI: 10.1103/physreva.3.130

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Auto-Ionizing States in the Alkali Atoms with Microsecond Lifetimes

P. D. Feldman, Robert Novick

Physical ReviewAug 5, 1967170 citations

Determination of the Fine and Hyperfine Structure and Lifetimes of the (1S2S2P) QUADRUPLET-P(0) Metastable Autoionizing States of LITHIUM-6 and LITHIUM-7.

Morris R. Levitt

Jan 1, 19680 citations

Zeeman quenching of the (1s2s2p) 4P metastable state in lithium

P. D. Feldman, Morris R. Levitt, Steven Trent Manson +1 more

PhysicaJan 1, 196711 citations

LIFETIME OF THE METASTABLE 23S1 STATE IN STORED Li+ IONS

Randall D. Knight

Lawrence Berkeley National LaboratoryJun 14, 20100 citations

Hyperfine quenching of the metastable P0,23 states in divalent atoms

S. G. Porsev, Andrei Derevianko

arXiv:physics/0312006Physical Review AApr 7, 2004117 citations

Spin exchange cross sections for collisions of metastable helium atoms with lithium atoms in the ground state

Victor A. Kartoshkin

The spin exchange and chemi-ionization cross sections for the metastable helium atom-lithium atom in the ground state system have been calculated. Using data on the interaction potentials obtained in this study, the spin exchange cross sections are determined for the first time for the He(23 S 1)-Li(22 S 1/2) system in the interval of collision energies from 5 × 10−3 to 16 eV.

Technical Physics LettersDec 1, 20070 citations

Physical Review A

Determination of Energies and Lifetimes of the Metastable Auto-Ionizing (1s2s2p)P4 States of Li6 and Li7 by a Zeeman-Quenching Technique

M. Levitt, Robert Novick, P. D. Feldman

Published Jan 1, 1971• 58 citations

Publisher

Abstract

A Zeeman-quenching atomic-beam method has been utilized for the determination of the fine- and hyperfine-structure energies and auto-ionization lifetimes of the metastable

(1s2s2p)^{4}P_{J}

states of

{\mathrm{Li}}^{6}

and

{\mathrm{Li}}^{7}

. Both the fine-structure intervals and the lifetimes of the

J=\frac{3}{2}

and

J=\frac{1}{2}

states are found to be in disagreement with existing theoretical calculations. The quenching of metastable lithium atoms in a nonuniform magnetic field can be satisfactorily described with the aid of the "adiabatic criterion." The present results also permit a quantitative evaluation of a proposal for producing polarized lithium nuclei.

DOI: 10.1103/physreva.3.130

Related papers

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

Determination of the Fine and Hyperfine Structure and Lifetimes of the (1S2S2P) QUADRUPLET-P(0) Metastable Autoionizing States of LITHIUM-6 and LITHIUM-7.

Morris R. Levitt

Jan 1, 19680 citations

Zeeman quenching of the (1s2s2p) 4P metastable state in lithium

P. D. Feldman, Morris R. Levitt, Steven Trent Manson +1 more

PhysicaJan 1, 196711 citations

LIFETIME OF THE METASTABLE 23S1 STATE IN STORED Li+ IONS

Randall D. Knight

A laser-induced fluorescence technique combined with the observation of spontane ous magnetic dipole photons from the highly metastable 2 3 S t state of Li + has been used to measure the radiative lifetime of this state.The ions are created by electron impact on a lithium A. Direct Determination of the Spontaneous Decay Curve .... 18 B. Direct Determination of the Number of Remaining Metastables 20 C. Indirect Determination of the Radiative Lifetime 23 IV.Ion Trap Theory and Performance 29 A. The RF-Quadrupole Ion Trap 29 B. The Ion Detection System 36 C. Ion Trap Performance 43 1.Ion storage 43 2. Ion distribution 50 V.Experimental Methods 56 A. The Vacuum System 56 B. The Lithium Oven and Hot Wire Detector 60 C. The Ion Trap and Electron Gun 62 D. The Magnetic Field 66 1. Detector operation ..... 73 2. Detector calibration 76 6.The Laser and Optical System 81 H.The Computer System 84 1. Timing and control .84 2. Operating and analysis programs 88 VI.Experimental Results 93 A. The Detection of Spontaneous Ml Photons 93 B. The Detection of Laser-Induced Photons 96 C. The Metastable Lifetime and Nonradiative Quenching .... 99 D. Procedures in Measuring the Radiative Lifetime 104 E. Data Reduction and Error Analysis Ill VII.Conclusion 119 Appendix A. Optical Pumping Calculations .121 A. The Magic Angle 121 B. The Optical Pumping Equations 123 C. Results of the Calculations .126 Appendix B. Measurements of the Ion Density Distribution 128 A. The Laser Scanning Technique 128 B. Experimental Results 130 Acknowledgements ....A laser-induced fluorescence technique combined with the observation of spontane ous magnetic dipole photons from the highly metastable 2 3 S t state of Li + has been used to measure the radiative lifetime of this state.The ions are created by electron impact on a lithium A. Direct Determination of the Spontaneous Decay Curve .... 18 B. Direct Determination of the Number of Remaining Metastables 20 C. Indirect Determination of the Radiative Lifetime 23 IV.Ion Trap Theory and Performance 29 A. The RF-Quadrupole Ion Trap 29 B. The Ion Detection System 36 C. Ion Trap Performance 43 1.Ion storage 43 2. Ion distribution 50 V.Experimental Methods 56 A. The Vacuum System 56 B. The Lithium Oven and Hot Wire Detector 60 C. The Ion Trap and Electron Gun 62 D. The Magnetic Field 66 1. Detector operation ..... 73 2. Detector calibration 76 6.The Laser and Optical System 81 H.The Computer System 84 1. Timing and control .84 2. Operating and analysis programs 88 VI.Experimental Results 93 A. The Detection of Spontaneous Ml Photons 93 B. The Detection of Laser-Induced Photons 96 C. The Metastable Lifetime and Nonradiative Quenching .... 99 D. Procedures in Measuring the Radiative Lifetime 104 E. Data Reduction and Error Analysis Ill VII.Conclusion 119 Appendix A. Optical Pumping Calculations .121 A. The Magic Angle 121 B. The Optical Pumping Equations 123 C. Results of the Calculations .126 Appendix B. Measurements of the Ion Density Distribution 128 A. The Laser Scanning Technique 128 B. Experimental Results 130 Acknowledgements ....

Lawrence Berkeley National LaboratoryJun 14, 20100 citations

Hyperfine quenching of the metastable P0,23 states in divalent atoms

S. G. Porsev, Andrei Derevianko

Hyperfine quenching rates of the lowest-energy metastable $^{3}P_{0}$ and $^{3}P_{2}$ states of Mg, Ca, Sr, and Yb atoms are computed. The calculations are carried out using ab initio relativistic many-body methods. The computed lifetimes may be useful for designing novel ultraprecise optical clocks and trapping experiments with the $^{3}P_{2}$ fermionic isotopes. The resulting natural widths of the $^{3}P_{0}\ensuremath{-}^{1}S_{0}$ clock transition are $0.44\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{25}\mathrm{Mg}$ , $2.2\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{43}\mathrm{Ca}$ , $7.6\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{87}\mathrm{Sr}$ , $43.5\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{171}\mathrm{Yb}$ , and $38.5\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{173}\mathrm{Yb}$ . Compared to the bosonic isotopes, the lifetime of the $^{3}P_{2}$ states in fermionic isotopes is noticeably shortened by the hyperfine quenching but still remains long enough for trapping experiments.Hyperfine quenching rates of the lowest-energy metastable $^{3}P_{0}$ and $^{3}P_{2}$ states of Mg, Ca, Sr, and Yb atoms are computed. The calculations are carried out using ab initio relativistic many-body methods. The computed lifetimes may be useful for designing novel ultraprecise optical clocks and trapping experiments with the $^{3}P_{2}$ fermionic isotopes. The resulting natural widths of the $^{3}P_{0}\ensuremath{-}^{1}S_{0}$ clock transition are $0.44\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{25}\mathrm{Mg}$, $2.2\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{43}\mathrm{Ca}$, $7.6\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{87}\mathrm{Sr}$, $43.5\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{171}\mathrm{Yb}$, and $38.5\phantom{\rule{0.3em}{0ex}}\text{mHz}$ for $^{173}\mathrm{Yb}$. Compared to the bosonic isotopes, the lifetime of the $^{3}P_{2}$ states in fermionic isotopes is noticeably shortened by the hyperfine quenching but still remains long enough for trapping experiments.

arXiv:physics/0312006Physical Review AApr 7, 2004117 citations

Spin exchange cross sections for collisions of metastable helium atoms with lithium atoms in the ground state

Victor A. Kartoshkin

Technical Physics LettersDec 1, 20070 citations

A Zeeman-quenching atomic-beam method has been utilized for the determination of the fine- and hyperfine-structure energies and auto-ionization lifetimes of the metastable

(1s2s2p)^{4}P_{J}

states of

{\mathrm{Li}}^{6}

and

{\mathrm{Li}}^{7}

. Both the fine-structure intervals and the lifetimes of the

J=\frac{3}{2}

and

J=\frac{1}{2}

{\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.

Hyperfine quenching rates of the lowest-energy metastable

^{3}P_{0}

and

^{3}P_{2}

states of Mg, Ca, Sr, and Yb atoms are computed. The calculations are carried out using ab initio relativistic many-body methods. The computed lifetimes may be useful for designing novel ultraprecise optical clocks and trapping experiments with the

^{3}P_{2}

fermionic isotopes. The resulting natural widths of the $^{3}P_{0}\ensuremath{-}^{1}S_{0}$ clock transition are

0.44\phantom{\rule{0.3em}{0ex}}\text{mHz}

for

^{25}\mathrm{Mg}

2.2\phantom{\rule{0.3em}{0ex}}\text{mHz}

for

^{43}\mathrm{Ca}

7.6\phantom{\rule{0.3em}{0ex}}\text{mHz}

for

^{87}\mathrm{Sr}

43.5\phantom{\rule{0.3em}{0ex}}\text{mHz}

for

^{171}\mathrm{Yb}

, and

38.5\phantom{\rule{0.3em}{0ex}}\text{mHz}

for

^{173}\mathrm{Yb}

. Compared to the bosonic isotopes, the lifetime of the

^{3}P_{2}

states in fermionic isotopes is noticeably shortened by the hyperfine quenching but still remains long enough for trapping experiments.