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1987-MG-03.jpg 205.0Kb JPEG image Thumbnail of ROTATIONAL SPECTRA OF $^{13}C$ TAGGED PROPYNE IN THE $V_{10}$ VIBRATION

Creators: Roberts, J. A.; An, I.; Tam, H.
Issue Date: 1987
Publisher: Ohio State University
Abstract: A study was made of the propyne and acetonitrile molecules on the rotational spectral components, $0\le J\le 4$, in low lying vibrational levels. Both the $^{12}C$ and isotopically substituted species of $^{13}C$ in $CH_{3}CCH$ and $CH_{3}CN$ molecules were studied. Recent studies on these two molecules in vibrational levels had shown strong resonance interactions within vibrations and combination vibration bands which do not appear to be explained by simple perturbation models. A study of the isotopically substituted components appeared to be promising. A comprehensive model was developed for the $^{12}CH_{3} {^{12}}C {^{12}}CH$ molecule and from the experimental results some resonance interactions were found which could be explored further by use of isotopic shifts in the spectra. We have been able initially to study the molecules $^{13}CH_{3} {^{12}}C^{12}CH, {^{12}}CH_{3} {^{13}}C^{12}CH$ and $^{12}CH_{3} {^{12}}C^{13}CH$ in the $v_{10} = 1$ and ground vibration for naturally abundant $^{13}C$. Thus far, the comprehensive model developed for this 12C species appears to hold but data are limited. Spectral studies made upon rotational components in the $V_{10} = 1, 2, 3$, and 4 vibrations of $CH_{3}CCH$ and rotational components of the $V_{8} = 1, 2$, and 3 vibrations of $CH_{3}C^{14}N$ and $CH_{3}C^{15}N$ indicated a departure from a molecular model based upon perturbation techniques but these results were used successfully to predict a number of components in the isotopic species. The major thrust of this paper is to present accurate experimental data for $\Delta J=+1$ rotations for $1\le J\le 4$ in the frequency range 15 to 95qHz and for the $V_{10} = 1$ for each isotope of propyne and for the $v_{8} = 1$ and 2 for the acetonitrile isotopes. From these data we have produced a molecular model which shows the trend in each molecular parameter with quantum number v, J, K, and $\ell$.
Description: $^{1}$ This work supported by Grant \#B-842 The Robert A. Welch Foundation, Houston, TX.
Author Institution: Dept. of Physics, North Texas State University
Other Identifiers: 1987-MG-3
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