He/sub 2/-(/sup 4/Pi/sub g/). -->. He/sub 2/(X/sup 1/. sigma. /sup +/) autodetachment energy spectrum: Assessment of the He/sub 2//sup -/ and He/sub 2/ ground-state potentials

Journal Article · Fri Apr 15 04:00:00 EDT 1988 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.37.2778· OSTI ID:5437909

Bae, Y K; Peterson, J R; Michels, H H; Hobbs, R H

The energy spectrum from the spin-forbidden electronic autodetachment from the metastable He/sub 2//sup -/(/sup 4/Pi/sub g/) ion has been measured. The single-peaked continuum, resulting from a vertical transition to the repulsive wall of the He/sub 2/(X/sup 1/..sigma../sub g//sup +/) ground state, has a maximum at 15.70 +- 0.15 eV. For a rotationally cool beam, the spectrum is inconsistent with the existing potentials of He/sub 2//sup -/ and He/sub 2/(X/sup 1/..sigma../sub g//sup +/). A suitable fit, neglecting rotational effects, would require an increase of 0.06 A in the calculated R/sub e/ of He/sub 2//sup -/. However, a very good fit can also be obtained from the existing potentials by assuming a rotationally hot (15 000 K) distribution. Surprisingly, both fits require contributions from levels v>0, which are known to undergo vibrational autodetachment to He/sub 2/(a/sup 3/..sigma../sub u//sup +/). For such contributions, the latter process must be exceptionally slow (<10/sup 6//s).

• Research Organization: SRI International, Menlo Park, California 94025
• OSTI ID: 5437909
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 37:8; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular &amp; Chemical Physics-- Atomic &amp; Molecular Properties &amp; Theory
74 ATOMIC AND MOLECULAR PHYSICS
AFFINITY
ANIONS
AUTOIONIZATION
CHARGED PARTICLES
ELECTRON DETACHMENT
ENERGY LEVELS
ENERGY SPECTRA
EXCITED STATES
HELIUM IONS
IONIZATION
IONS
METASTABLE STATES
MOLECULAR IONS
SPECTRA