Fourier Transform Emission Spectroscopy of the A6Σ+-X6Σ+ System of CrH: Evidence for a 4Σ+ Lowest Excited State

✍ Scribed by R.S. Ram; C.N. Jarman; P.F. Bernath

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 493 KB
• Volume: 161
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1993.1250

✦ Synopsis

The emission spectrum of (\mathrm{CrH}) has been observed in the near-infrared region from (10000-) (13500 \mathrm{~cm}^{-1}) using a Fourier transform spectrometer. Compared with the previous work on this molecule, the present spectra provide greatly improved measurements of the line positions of the (A^{6} \Sigma^{+}-X^{6} \Sigma^{+})electronic transition. The rotational analysis of the (0-0) band bas been performed providing the following principal molecular constants: (T_{00}=11552.6848(10) \mathrm{cm}^{-1}, B^{\prime}=) (5.271996(29) \mathrm{cm}^{-1}), and (B^{\prime \prime}=6.1317406(19) \mathrm{cm}^{-1}). As was first noted by Kleman and Uhler, the excited state is perturbed. By correcting a few misassignments in the previous work, we conclude that a nearby (a^{4} \Sigma^{+})state is responsible for the perturbation. The (a^{4} \Sigma^{+})state has an approximate band origin (T_{00}=11186 \mathrm{~cm}^{-1}) and a preliminary rotational constant (B_{0}=6.10 \mathrm{~cm}^{-1}). This state lies below the (A^{b} \Sigma^{+})state and is, therefore, the lowest lying excited state. & 1993 Academic Press. Inc.