THE FORBIDDEN I 1 Σ − – X 1 Σ + ABSORPTION BANDS OF CARBON MONOXIDE
1966; NRC Research Press; Volume: 44; Issue: 12 Linguagem: Inglês
10.1139/p66-249
ISSN1208-6045
AutoresG. Herzberg, J. D. Simmons, Arnold M. Bass, S. G. Tilford,
Tópico(s)Spectroscopy and Laser Applications
ResumoThe forbidden I 1 Σ − –X 1 Σ + transition of CO has been observed in absorption at high resolution in the vacuum ultraviolet region. As expected for a 1 Σ − – 1 Σ + transition, the bands consist of single Q branches, in which the lines of lowest J are either missing or very weak. Although the selection rule prohibiting Σ − –Σ + transitions is rigorous for dipole radiation at zero rotation, the I 1 Σ − –X 1 Σ + transition can occur for higher rotational levels because of Coriolis interaction with the A 1 Π state, which lies very close to the I 1 Σ − state.Eight bands of the I–X system have been analyzed and from them the rotational and vibrational constants of the I 1 Σ − state have been determined. Previous information on this state was based entirely on the study of perturbations in the A 1 Π state. The corresponding perturbations in the I 1 Σ − state have now been observed. In addition, small "vibrational" perturbations in the ν = 4 and 5 levels (probably caused by interactions with the a 3 Π state) are found.
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