Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9589676 | Journal of Molecular Spectroscopy | 2005 | 8 Pages |
Abstract
Emission bands attributed to the NbS radical have been observed in the near infrared and visible regions with FTS techniques using an electrodeless 2450 MHz discharge as a source. Transitions within the doublet and quartet manifolds were recorded at high resolution. The present paper gives the first rotational analysis of this molecule. Numerous bands within the doublet and quartet manifolds have been analyzed, resulting in the characterization of seven different electronic states, three in the doublet and four in the quartet manifold. The states have been labeled in analogy with NbO. The analyzed electronic states are: X4Σâ, C4Σâ, Aâ²4Φ, D4Î, a2Î, c2Î , and e2Φ. Four additional substates in the doublet manifold have also been analyzed. In all, 27 vibrational sublevels have been included in the analysis, the total number of rotational lines being about 18 000. The positions of the analyzed transitions are: C4Σâ â X4Σâ near 15 670 cmâ1, D4Πâ Aâ²4Φ near 7740 cmâ1, c2Î Â â a2Î near 5850 cmâ1 and e2Φ â a2Î near 8500 cmâ1. The overall picture is consistent with the corresponding analysis of NbO. However, three energy separations could not be derived from the experimental data in the case of NbS, i.e., the a2Îâ X4Σâ, Aâ²4Φâ X4Σâ and a2Î5/2-a2Î3/2 splittings. These were set to 4992, 5490, and 992 cmâ1, respectively, from preliminary ab initio calculations. In this way, a tentative energy level scheme could be drawn. The first order spin-orbit parameter of the Aâ²4Φ state was indeterminable from the experimental data and was set to the value 170 cmâ1, derived from the same calculations.
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Authors
O. Launila,