Identification of Two 3Πu ← X3Σ−g Transitions of 16O2 near 93 850 and 95 360 cm−1

✍ Scribed by K. Ito; K.P. Huber; K. Yoshino; M. Ogawa; Y. Morioka

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 610 KB
• Volume: 171
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1995.1098

✦ Synopsis

The one-photon absorption spectrum of molecular oxygen in the photoionization threshold region has been recorded at high resolution (\left(\lambda / \Delta \lambda=2 \times 10^{5}\right)) against the background continuum of a synchrotron radiation source. The room temperature spectrum as well as the rotationally cold absorption of a supersonically expanding jet ( (T_{\mathrm{rot}} \approx 20 \mathrm{~K}) ) have been registered on photographic plates. The drastically reduced complexity of the jet spectra has led to the unambiguous identification of two ({ }^{3} \mathrm{II}{u}) vibronic levels of ({ }^{16} \mathrm{O}{2}) at 93850 and (95360 \mathrm{~cm}^{-1}); rotational and (\Lambda) type doubling parameters have been determined. In addition. the upper state of a previously reported strong band of ({ }^{16} \mathrm{O}{2}\left({ }^{18} \mathrm{O}{2}\right.) ) at (86733(86697) \mathrm{cm}^{-1}) (Ogawa et al. J. Mol. Spectrosc. 55, 425 429. 1975) has tentatively been attributed to (v=0) of the bound second adiabatic ({ }^{3} \mathrm{II}{u}) potential arising from the strong interaction of the (\cdots \pi{u}^{4} \pi_{g} \cdot 3 p \sigma_{u}) Rydberg with the (\cdots \pi_{u}^{4} \pi_{g} \sigma_{u}) valence configuration (Buenker (\boldsymbol{e}) al., Chem. Phys. Lett. 34, 225-231, 1975; 42, 383-389. 1976). (ci 1995 Academic Press, Inc.