### Abstract

We measured the cusp electron production associated with target ionization at the impact of a 400-keV pure2[Formula Presented]S He beam and a mixed beam containing all three long-lived He states, i.e., 1[Formula Presented]S,n2[Formula Presented]S, and 2[Formula Presented]S. Using the results of an earlier experiment [Kuzel et al., Phys. Rev. A 48, R1745 (1993)], we estimated the cross section for both metastable states of He. We found that the cusp for the 2[Formula Presented]S state is much larger and sharper than for the 2[Formula Presented]S state. The peaks are manifestations of excitation of low-lying virtual or weakly bound states of the [Formula Presented] ion at the 2[Formula Presented]S and 2[Formula Presented]S thresholds.

Original language | English |
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Pages (from-to) | R14-R17 |

Journal | Physical Review A - Atomic, Molecular, and Optical Physics |

Volume | 55 |

Issue number | 1 |

DOIs | |

Publication status | Published - Jan 1 1997 |

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### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics

### Cite this

*Physical Review A - Atomic, Molecular, and Optical Physics*,

*55*(1), R14-R17. https://doi.org/10.1103/PhysRevA.55.R14