On a Metastable Energy State of the Negative Helium Ion

Holøien, E.; Midtdal, John

doi:10.1088/0370-1298/68/9/306

Cited by 81 publications

(10 citation statements)

References 5 publications

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“…However, the He À ion has been reported in beam experiments since 1925 [1]. In 1955, Holøien and Midtdal [2] established theoretically that the metastable 1s2s2p 4 P o J state in He À is bound with respect to the lowest excited state of neutral He, 1s2s 3 S e (cf. Fig.…”

mentioning

confidence: 99%

Precision Lifetime Measurements ofHe−in a Cryogenic Electrostatic Ion-Beam Trap

et al. 2009

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We have developed a small purely electrostatic ion-beam trap which may be operated in thermal equilibrium at precisely controlled temperatures down to 10 K. Thus, we avoid magnetic field induced mixing of quantum states and may effectively eliminate any influence from absorption of photons from blackbody radiation. We report the first correction-free measurement of the lifetime of the 1s2s2p {4}P{5/2}{0} level of 4He(-) yielding the high-precision result 359.0 +/- 0.7 micros. This result is an essential proof-of-principle for cryogenic electrostatic storage rings and traps for atomic and molecular physics.

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confidence: 99%

Precision Lifetime Measurements ofHe−in a Cryogenic Electrostatic Ion-Beam Trap

et al. 2009

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“…However, to limit the extent of the CI to a manageable size, two electrons were constrained to cr-type orbitals in all configurations. The full CI expansions subject to this constraint were 4 n g , 4 n u (1056); % + , 4 2 + (1292); 3 …”

mentioning

confidence: 99%

Electronic Structure of the Helium Molecular AnionHe2−

Michels¹

1984

Phys. Rev. Lett.

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The recently discovered He 2~ ion is examined by means of configuration-interaction wave functions constructed from an extended Slater-type-orbitals basis. We find that the 4 n g state of He 2~ is bound relative to the a 2 Xu state of He 2 . The calculated electron affinity is 0.233 eV compared to 0.077 eV for the He" [ 4 P°] ion. This anion decays through the long-lived 4g component with r ~ 350 /xsec and the much shorter-lived 4g> TS components with r ~ 10 /xsec.

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“…The He − ions are mostly quadruplet metastable state because other He − states are dissociated immediately. 7 The lifetimes of states with total angular momentum of J = 3/2 and 5/2 are 10 μs and 300 μs, respectively; they exist equally in the beam. 8,9 He − (1s2s2p) 4 S 3/2,5/2 → He 0 (1s 2 ) 1 S 0 + e.…”

Section: B Beam Neutralizationmentioning

confidence: 98%

Development of a He- and He0 beam source for alpha particle measurement in a burning plasma

Tanaka

Sasao

Terai

et al. 2012

Review of Scientific Instruments

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Proof of principle experiments of neutral helium beam production for alpha particle diagnostics was carried out on a test stand. Negative helium ions were produced in the Li charge exchange cell, in which stable and long time operation was possible. He(-) beam was accelerated to 157 keV. Finally, He(0) beam was successfully produced after the flight in the drift-tube through the auto-electron-detachment process from He(-) to He(0). A neutral beam detector using a pyroelectric device was also developed to measure He(0) beam intensity. The metastable component in the neutral helium beam was found to be less than 2%.

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On a Metastable Energy State of the Negative Helium Ion

Cited by 81 publications

References 5 publications

Precision Lifetime Measurements ofHe−in a Cryogenic Electrostatic Ion-Beam Trap

Precision Lifetime Measurements ofHe−in a Cryogenic Electrostatic Ion-Beam Trap

Electronic Structure of the Helium Molecular AnionHe2−

Development of a He- and He0 beam source for alpha particle measurement in a burning plasma

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