Electroionization study of ethylene: ionization and appearance energies, ion-pair formations, and negative ions

Abstract

Monoenergetic electron-impact threshold ionization and appearance curves of very high sensitivity of ethylene and all fragments containing at least one carbon atom are analyzed in detail. Ionization or appearance energies are measured for all ions, including the [Formula: see text] fragment. Structures are observed in the immediate [Formula: see text] threshold region, which are attributed to hot bands and to Rydberg autoionizing states. [Formula: see text],[Formula: see text] and [Formula: see text] ion-pair formations are reported for the first time. Simultaneous production of positive and negative ions is seen to be a common mechanism by electron impact. Appearance energies of some fragments are several electron volts lower than those of previous works.