FOURIER TRANSFORM INFRARED EMISSION SPECTRA OF MgH AND $MgH_{2}$
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Date
2003
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Publisher
Ohio State University
Abstract
We have recorded the vibration-rotation spectra of gaseous MgH and $MgH_{2}$ in emission using a furnace-discharge source. The molecules were generated at $650^{\circ}C$ and 333 mA discharge current with magnesium and a mixture of argon and hydrogen gases. The recorded spectra contained several emission bands, as well as the absorption of atmospheric $H_{2}O$. The highest signal-to-noise ratio for MgH lines was about 200. Three vibrational bands, $v=1-0$ to $v=3-2$, for ${^{24}}MgH$ and two vibrational bands for ${^{25}}MgH$ and ${^{26}}MgH$ were observed in the $2\Sigma^{+}$ ground electronic state. The analysis of the infrared data combined with our previous data on the $B^{\prime}-X$ electronic transition will lead to an improved potential energy curve for the ground state using a direct-potential-fit approach. In addition to MgH, we found the antisymmetric stretching mode $(\nu_{3})$ of ${^{24}}MgH_{2}$ and three hot bands involving $\nu_{2}$ and $\nu_{3}$ in our spectrum. The bands were rotationally analyzed and the spectroscopic constants were determined. The $MgH_{2}$ molecule has a linear structure with an $R_{0}$ Mg-H bond length of $1.703327(3) \AA$.
Description
Author Institution: Department of Chemistry, University of Waterloo