MICROWAVE SPECTRUM OF TRANS-1-CYANO-1,3-BUTADIENE

Author Institution: Division of Pure Physics, National Research Council“The assignment of forty \emph{a} and \emph{b}-type lines has yielded the following values for the three rotational constants and the four (in this case) independent first order centrifugal distortion constants: \[ \begin{array}{lll} A = 26,243.15_{5}Mc/s& D_{J} = 1.18 \times 10^{-4}\;Mc/s\\ B=1,443.611’’& D_{JK} = 1.588 \times 10^{-2}{‘ ‘}\\ C=1,368.129’’ &D_{K} = 1.160’’\\ &\delta_{J} = 1.58 \times 10^{-5}{‘ ‘} \end{array} \] The remaining two distortion constants, dependent on those above, are $R_{5} = 1.58 \times 10^{-3}$ Mc and $R = 1 \times 10^{-6}$ Mc. The inertial defect $\Delta = I_{c} - I_{a} - I_{b}$ is +0.0572 amu \{A}$^{2}$, indicating that the molecule is planar. Stark effect measurements have yielded a diploe moment of 4$4.38 \pm 0.04$ D, with $\mu_{a} = 4.28 \pm 0.04$ D and $\mu_{b} = 0.95 \pm 0.02$ D.