MICROWAVE RELATIVE INTENSITIES AND THE FUNDAMENTAL VIBRATION FREQUENCIES OF KETENE$^{\ast}$

$^{\ast}$The research was made possible by support extended Harvard University by the Office of Naval Research under ONR Contract Nonr 1866, Task Order XIV.Author Institution: Mallinckrodt Chemical Laboratory, Harvard UniversityRelative intensity measurements, accurate to a few percent, made on pure rotational transitions of $CH_{2}CO, CHDCO$ and $CD_{2}CO$ in excited vibrational states, have enabled the three lowest fundamental frequencies of these molecules to be determined and positively assigned. The lowest frequency in each case is nearly $100 cm^{-1}$ lower than any value previously given from gasphase infrared data. The microwave values have been substantiated by the low temperature infrared spectra of the solid ketenes between $300-4,000 cm^{-1}$ (run at Tufts University by Mr. Kee Rhee in Professor M. Kent Wilson's laboratory). Moreover, the solid-state spectra allow a complete assignment of all fundamentals to be given for the three isotopic molecules. The effects of the new assignments on the potential function and thermodynamic calculations will be discussed. In addition, the related problem of diazomethane will be considered