Knowledge Bank

The absorption spectra of $C2H4$ and $C2D4$ were investigated under high resolution from 1500A to 2000A. It proved to be possible to determine vibrational constants and approximate anharmonicity constants for the R and V states as well as torsional frequencies. The hindering potential barrier in the R state was estimated to be $700-1200cm-1$ and in the V state to be less than $21,700cm-1$. Treatment of the strong N-V continuum as the dissociation of a free rotator-vibrator gave a dissociation energy of $7.4\pm .3$ electron volts for the V state.