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Author(s):Kobayashi, Kaori
Contributor(s):Moriwaki, Yoshiki ; Matsushima, Fusakazu ; Sumi, Tatsuki
Abstract:Calcium monohydride CaH is an astronomical molecule identified in the Sun and other stars by using visible transitions. We have found many new vibrational levels of the B/B$'$ state using Laser Induced Fluorescence (LIF) from the visible to ultraviolet region. $\footnote{K. Watanabe, N. Yoneyama, K. Uchida, K. Kobayashi, F. Matsushima, Y. Moriwaki, S. C. Ross, \textit{Chem. Phys. Lett.} \underline{\textbf{657}}, 1 (2016).}$$^,$ $\footnote{K. Watanabe, I. Tani, K. Kobayashi, Y. Moriwaki, S. C. Ross, \textit{Chem. Phys. Lett.} \underline{\textbf{710}}, 11 (2018).}$ In the analysis of these transitions, we fixed the molecular constants in the ground state to those analyzed for the A$^2\Pi$, B$^2\Sigma^+\rightarrow$ X$^2\Sigma^+$ in 12000 - 17000 cm$^{-1}$ region and the $v=v'+1\rightarrow v'$($v'=0-3$) in X$^2\Sigma^+$ transitions by Shayesteh et al. \footnote{A. Shayesteh, R. S. Ram, and P. F. Bernath, \textit{J. Mol. Spectrosc.} \underline{\textbf{288}}, 46 (2013).}$^,$\footnote{A. Shayesteh, K. A. Walker, I. Gordon, D. R. T. Appadoo, and P. F. Bernath, \textit{J. Mol. Struct.}, \underline{695} (2004).} The pure rotational spectra in the ground state have been reported and hyperfine structure was analyzed. $\footnote{ C. I. Frum, J. J. Oh, E. A. Cohen, H. M. Pickett, \textit{ Astrophys. J. Lett.} \underline{\textbf{408}}, L61 (1993).}$ $\footnote{ W. L. Barclay Jr., M. A. Anderson, L. M. Ziurys, \textit{ Astrophys. J. Lett.} \underline{\textbf{408}}, L65 (1993).}$ However, the range was limited up to $N$ = 2-1. the highest frequency was about 500 GHz. In this study, we will report our new measurement in the terahertz region. The spectra were taken by using tunable far-infrared spectrometer at the University of Toyama. Calcium monohydride was produced in a cell where Ca vapor was introduced by heating Ca at 750$^\circ$C and DC discharge was applied under H$_2$ and He gas environment. So far the highest frequency we observed was about 1.5 THz. The accurate rest frequencies and molecular constants will be provided.
Issue Date:23-Jun-20
Publisher:International Symposium on Molecular Spectroscopy
Citation Info:APS
Date Available in IDEALS:2020-06-26

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