| Autor: |
Stark, G., Herde, H., Lyons, J. R., Heays, A. N., de Oliveira, N., Nave, G., Lewis, B. R., Gibson, S. T. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 6/25/2018, Vol. 148 Issue 24, pN.PAG-N.PAG, 8p, 1 Chart, 7 Graphs |
| Abstrakt: |
Photoabsorption cross sections and oscillator strengths for the strong, predissociating vibrational bands, v ≥ 11, in the S 2 B Σ u − 3 − X Σ g − 3 ( v , 0 ) system are reported. Absorption measurements were undertaken on S2 vapor produced by a radio-frequency discharge through H2S seeded in helium, and also in a two-temperature sulfur furnace, at temperatures of 370 K and 823 K, respectively. S2 column densities were determined in each source by combining experimental line strengths in low- v non-predissociating B − X bands ( v < 7) with calculated line f-values based on measured radiative lifetimes and calculated branching ratios. The broad-band capabilities of two vacuum-ultraviolet Fourier-transform spectrometers, used with instrumental resolutions of 0.22 cm−1 and 0.12 cm−1, respectively, allowed for simultaneous recordings of both non-predissociating and predissociating bands, thus placing the predissociating-band cross sections on a common absolute scale. Uncertainties in the final cross section datasets are estimated to be 15% for the 370-K vapor and 10% for the 823-K vapor. The experimental cross sections are used to inform a detailed predissociation model of the B( v ) levels in Paper II [Lewis et al., J. Chem. Phys. 148, 244303 (2018)]. For astrophysical and other applications, this model can be adjusted simply to provide isotopologue-specific cross sections for a range of relevant temperatures. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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