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Low-energy measurements of electron capture by multicharged ions from excited hydrogen atoms

Conference ·
DOI:https://doi.org/10.1063/1.43757· OSTI ID:10188296
 [1];  [2];  [3];  [4];  [5]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Alcorn State University, Lorman, MS (United States)
  3. University Coll., London (United Kingdom)
  4. Universite Catholique de Louvain, Louvain-la-Neuve (Belgium)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States)
For very low collision energies electron capture from excited hydrogen by multicharged ions is characterized by enormous cross sections, the predicted maximum being comparable to the geometric size of the Rydberg atom. The ion-atom merged-beams technique is being used to study these collisions for the variety of charge states and the wide range of energies (0.1 to 1000 eV/amu) accessible to the apparatus. A neutral D beam containing a Rydberg atom population proportional to 1/n{sup 3} is produced by collisional electron detachment of 8 key D{sup {minus}} in N{sub 2} gas. An applied electric field results in a truncation of the maximum principal quantum number present in the beam in the range (n=24-11) depending on the strength of the field applied. This beam is then merged with 0{sup 3+} or 0{sup 5+} ion beams at low relative collision velocities where the resultant beam-beam signal of D{sup +} due to electron loss is dominated by electron capture. From the sharp decrease in the observed beam-beam signal as the electric field increases it is inferred that the electron capture cross section scales as n{sup 4} increasing towards n{sup 5} for collision energies below 1 eV/amu.
Research Organization:
Oak Ridge National Lab., TN (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC05-84OR21400; AC05-76OR00033
OSTI ID:
10188296
Report Number(s):
CONF-920948--5; ON: DE93001642
Country of Publication:
United States
Language:
English