# AN INFRA-RED ELECTRONIC TRANSITION OF CoC

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 Title: AN INFRA-RED ELECTRONIC TRANSITION OF CoC Creators: Barnes, M.; Merer, A. J.; Metha, G. F. Issue Date: 1995 Abstract: The laser induced fluorescence spectrum of jet-cooled CoC has been measured at high resolution following the reaction of laser-ablated cobalt atoms with methane. The ${^{2}}\Sigma^{+}$ ground state is an unusually good example of Hund's case $(b_{\beta S})$ coupling. Since $^{59}Co$ has a nuclear spin l = 7/2, each rotational level is split by the Fermi contact interaction into G = 3 and 4 components, where G = I + S; the splitting is roughly 4b, and for N = 0 is more than $0.5 cm^{-1}$. The ${^{2}}\Sigma^{+}$ state begins to uncouple toward case $(b_{\beta J})$ at higher N values. We have identified three upper state $\Pi$ levels giving rise to bands at $13078 cm^{-1} (\Omega = 3/2), 13344 cm^{-1} (\Omega = 1/2)$ and $13428 cm^{-1} (\Omega = 3/2)$; only transitions to the first two are strong enough to be recorded at high resolution. There are three more $\Pi$ levels approximately $1000 cm^{-1}$ higher in energy. Furthermore, we have identified a very low-lying ${^{2}}\Delta_{i}$ state, for which the $\Omega = 5/2$ and 3/2 levels lie at 222 and $1173 cm^{-1}$, respectively. Laser excitation of the ${^{2}}\Pi_{3/2} - {^{2}}\Delta_{5/2}$ transition has been observed by monitoring the strong ${^{2}}\Pi_{3/2} - {^{2}}\Sigma^{+}$ emission, which has allowed the ${^{2}}\Delta_{5/2}$ state to be characterized at high resolution. A total of 879 hyperfine transitions between the various ${^{2}}\Pi_{1/2}, {^{2}}\Pi_{3/2} {^{2}}\Delta_{5/2}$ and ${^{2}}\Sigma^{+}$ states has been assigned and fitted. The $\Pi$ and $\Delta$ states were treated with a case (c) model and the ${^{2}}\Sigma^{+}$ state in case $(b_{\beta S})$, following the full derivation of the appropriate matrix elements. URI: http://hdl.handle.net/1811/29503 Other Identifiers: 1995-MH-08