THE EXCITED VIBRATIONAL STATES OF PROPYNE AROUND 1000 $cm^{-1}$ BY MICROWAVE AND INFRARED SPECTROSCOPIES.

Author Institution: Laboratoire de Spectroscopie Hertzienne (URA CNRS), Universite de Lille I.; Facult\'{e}s Universitaires N-D dela Paix., Laboratoire de Spectroscopie Mol\'{e}culaire; Laboratoire de Physique, Mol\'{e}culaire et ApplicationsWe have recently determined the molecular constants of propyne ($CH_{3}C=CH$) in its ground vibrational state and in its low lying excited states $(\nu_{10} = 1 ; 2$ and $\nu_{a} = 1)$. We are now studying the next states which ly between 900 and $1100 cm^{-1}$. This polyad includes the levels: $\nu_{5} = 1, \nu_{8} = 1, \nu_{9} = \nu_{10} = 1$ and $\nu_{10} = 3$. The rotational spectra of these states were measured up to 470 GHz. $\nu_{5} \nu_{8}$ and a part of $(\nu_{9} + \nu_{10})^{0}$ bands were analyzed at $10 \mu$m. But most of the information concerning $\nu_{9} = \nu_{10}= I$ was found by studying the hot bands $(\nu_{9} + \nu_{10})^{2} - \nu_{10}$ and $(\nu_{9} + \nu_{10})^{0} - \nu_{10}$ on diode laser spectra at $16 \mu$m. The information on the $\nu_{10} = 3$ levels was obtained from the hot bands at $30 \mu$m on a Fourier transform spectrum. A global fit of the upper state energies and rotational frequencies gives the molecular parameters