ROTATIONAL ANALYSIS OF THE EXCITED STATES OF METHYL CYANIDE AND METHYL CYANIDE-$D_{3}$.

Author Institution: Laboratoire de Spectroscopie Hertzienne, UA CNRS 249, Bat. P5, Universit\'{e} de Lille 1The rotational spectrum of $CD_{3}CN$ has been measured up to 1500 GHz for the ground state and up to 400 GHz for several excited vibrational states: $v_{g}=1, 2,3, v_{4}=1, v_{7}=1, v_{3}=1$ and $v_{6}=1$. Many of these states are located between 700 and $1100 cm^{-1}$ and some of them are involved in the submillimeter emissions of $CD_{3}CN$. The different types of interactions between these levels are discussed. A comparison is made with CH3CN, which shows a similar diagram of energy levels