Assignment of the 3Πu←X 3Σ−g bands of O2 observed in the region 1040–1200 Å
| Autor: | Brenton Lewis, Marshall L. Ginter, Stephen Gibson, J. P. England |
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| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | The Journal of Chemical Physics. 104:2765-2772 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.471099 |
| Popis: | A comprehensive vibronic assignment of the 3Πu states in the energy region approaching the first ionization threshold of O2 is presented for the first time. Measurements of seventeen 3Πu←X 3Σ−g bands in the 85 800–93 000 cm−1 region of the ground‐state photoabsorption spectra of 16O2 and 18O2 at 79 K are reported, including six bands in the spectrum of 18O2 for the first time. Irregularities in vibrational spacings and in the extent of broadening by predissociation are shown to result from Rydberg‐valence interactions. The observed transitions have been assigned, using semiempirical modeling of the 3Πu Rydberg‐valence interactions based on the coupled‐channel Schrodinger equations technique, to two vibrational progressions with upper states which we call F 3Πu and F′ 3Πu. The F and F′ states are formed from the avoided crossings of the npσu (n=3–5) Rydberg potential‐energy curves by the lowest repulsive 3Πu valence potential‐energy curve. |
| Databáze: | OpenAIRE |
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