## HIGH RESOLUTION FOURIER TRANSFORM EMISSION SPECTROSCOPY OF THE $\tilde{A}^2\Sigma^+ - \tilde{X}^2\Pi$ TRANSITION OF THE BrCN$^+$ ION

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Ohio State University##### Abstract:

The BrCN$^+$ ion was produced by Penning ionization of BrCN with metastable He$^*$, and the near-infrared emission in the 690 - 870 nm region was measured by Fourier transform spectrometer. Thirteen vibronic bands of the $\tilde{A}^2\Sigma^+ - \tilde{X}^2\Pi$ transition of $^{79}$BrCN$^+$ and $^{81}$BrCN$^+$ were observed. The rotational analysis was performed for the $\tilde{A}^2\Sigma^+(000) - \tilde{X}^2\Pi_{\Omega}(000)$ and $\tilde{A}^2\Sigma^+(000) - \tilde{X}^2\Pi_{\Omega}(010)$ transitions, both for the $\Omega=3/2$ and 1/2 spin components. \\ Molecular constants, including the effective rotational constant, centrifugal distortion constant, $\Lambda$-type doubling constant in the $\tilde{X}^2\Pi_{1/2}$ state, and spin-rotation interaction constant in the $\tilde{A}^2\Sigma^+$ state, were determined from the observed spectrum. Spin-orbit interaction constants for the $\tilde{X}^2\Pi$ ground state were determined to be $-$1476.4669(48) and $-$1476.4841(60) cm$^{-1}$, respectively, for $^{79}$BrCN$^+$ and $^{81}$BrCN$^+$. The $r_0$-structures for the $\tilde{X}^2\Pi$ and $\tilde{A}^2\Sigma^+$ states of BrCN$^+$ were derived to be compared with that for the $\tilde{X}^1\Sigma^+$ state of BrCN. The geometrical change of the BrCN$^+$ ion from the BrCN molecule was turned out to be small. \\ Due to the Renner-Teller effect, the $\tilde{X}^2\Pi$(010) state was split into four components, $\mu ^2\Sigma$, $\kappa ^2\Sigma$, and $^2\Delta_{P}$ ($P=5/2$ and 3/2), and the rotational analysis was performed both for the $\tilde{A}^2\Sigma^+ - \mu^2\Sigma$ and $\tilde{A}^2\Sigma^+ - \kappa^2\Sigma$ transitions. For the $\mu^2\Sigma$ and $\kappa^2\Sigma$ vibronic states, $\Omega$-type doubling constants were determined as well as the rotational constants and centrifugal distortion constants. Renner parameter $\epsilon$ for the $\tilde{X}^2\Pi$ state was determined to be $-0.185$ from the $\Omega$-type doubling constants for both the isotopic species.

##### Description:

Author Institution: Department of Chemistry, Faculty of Science, Kyushu University 33, Hakozaki, Higashiku,; Fukuoka 812-8581, Japan

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article##### Other Identifiers:

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