Knowledge Bank

The ground state rotational absorption spectra of $C6H5CHO$ and $C6H5CDO$ have been investigated in the 26.5 to 40 GHz region and have been correlated with the assignments of previous work.$\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$ Preliminary values for the rotational constants for $C6H5CHO$ are $A=1204.6,B=1564.2,C=5235.6$ and for $C6H5CHO$ are $A=1183.9,B=1540.7,$ and $C=5107.3$. Study of the torsional vibrational states is in progress and results of this study will be presented. An estimate of the height of the barrier to internal rotation based on accurate relative intensity measurements will also be presented. This work has been supported in part by the National Aeronautics and Space Administration. $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$T. Kojima, C.R. Quade and C.C. Lin, Bull. Am. Phys. Soc. 7, 44 (1962).