A REINVESTIGATION OF THE ABSORPTION SPECTRUM OF ETHYLENE

Author Institution:The vacuum ultraviolet absorption spectra of ethylene, ethylene-$d_{4}$ and all partially deuterated ethylenes have been measured and analyzed. The resultant assignments differ somewhat from prior assignments. The observed electronic systems are assigned as transitions to the ns, 3p, ndo, and $B_{2u} nd\delta$ Rydberg states and their vibrational sub-bands. The anomalies reported concerning the $\nu_{2}$ fundamental are resolved. In several of the molecules, transitions are observed to both odd and even quanta of the torsional vibration. Theoretical predictions of the ethylene spectrum are assessed on the basis of the present assignments