The role of high Rydberg states in the generation of negative ions in negative-ion discharges
The generation of substantial yields of H{sup {minus}} ions in a laser excited H{sub 2} gas has been reported by Pinnaduwage and Christoforu. These H{sup {minus}} yields have been attributed to (2 + 1) REMP photoexcitation processes leading to dissociative attachment of doubly-excited or superexcited states (SES), or dissociative attachment of high Rydberg product states. The new feature of these experiments is the implied large dissociative attachment rates, of order 10{sup {minus}6} cm{sup 3} sec{sup {minus}1}, values that are orders-of-magnitude larger than the dissociative attachment of the vibrationally excited levels of the ground electronic state. While these laser excitations are not directly applicable to a hydrogen negative-ion discharge, the implication of large dissociative attachment rates to the high Rydberg states may affect both the total negative-ion density and the interpretation of discharge performance. Within the discharge energetic electrons will collisionally excite the higher Rydberg states, and the relative contribution of the dissociative attachment of these states when compared with the dissociative attachment to the ground state vibrational levels, is the topic of this paper.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 201795
- Report Number(s):
- UCRL-JC-122525; CONF-9510304-2; ON: DE96005313; TRN: 96:008373
- Resource Relation:
- Conference: Joint meeting of the 7. international symposium on the production and neutralization of negative ions and beams and the 6. European workshop on the production and application of light negative ions, Upton, NY (United States), 23-27 Oct 1995; Other Information: PBD: 28 Nov 1995
- Country of Publication:
- United States
- Language:
- English
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