Near-Threshold Electron-Impact Excitation of the Low-Lying Rydberg States of Ethylene

Excitation functions for the 3 B 3u π → 3s and 3 B 1g and 1 A g π → 3p Rydberg states of ethylene have been measured and found to display structure due to the decay of core-excited anion states. Evidence is also provided that the π -1 (3s) 2 anion state undergoes significant decay to the π → π* singlet state in highly twisted configurations.