Photoionization of atomic oxygen from 920 to 650 Å
- Argonne National Laboratory (ANL), Argonne, IL (United States)
Atomic oxygen was produced in a low pressure gas discharge and was equilibrated in a small chamber to eliminate electronically excited species prior to the formation of an atomic beam which was photoionized. Relative photoionization cross sections were measured from 920 to 650 Å at a wavelength resolution (FWHM) of 0.42 Å. From the ratio of threshold intensities corresponding to ionization from the ³P₂, ³P₁, and ³P₀ states of Ol, the beam temperature was estimated to be 375 ± 25°K. Autoionization structure was observed corresponding to all of the transitions seen in absorption by Huffman, Larrabee, and Tanaka, including those transitions for which autoionization is forbidden on the basis of Russell-Saunders coupling. The seven lowest energy autoionizing lines were measured at a wavelength resolution (FWHM) of 0.16 Å. The distribution of intensities within a multiplet corresponded to the theoretical intensities predicted for an approximately 375°K beam in all but two cases. These notable exceptions were the two most intense autoionization peaks in the spectra, both of which were forbidden in pure Russell-Saunders coupling. The anomalous intensity distributions may be attributed to competition from emission which preferentially robs intensity from selected transitions within a multiplet, to nonstatistical autoionization probabilities, or to perturbations which alter the relative absorption intensities within a multiplet.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- US Atomic Energy Commission (AEC)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 1169895
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 11 Vol. 59; ISSN JCPSA6; ISSN 0021-9606
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
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