Insights into the C4H8+center dot potential energy surface: Fourier transform ion cyclotron resonance studies of ion-molecule reactions of D-labeled partners

Reactions of [ethylene](+.) with ethylene and of [acetylene](+.) with ethan e were studied by Fourier transform ion cyclotron resonance spectrometry us ing labeled reactants, The results confirm and clarify the different steps of the mechanism proposed previously and elaborated with other methods. The [[acetylene](+.), ethane] system can either dissociate to give the ethyl c ation product, or Isomerize into [[ethylene](+.), ethylene], The latter sys tem can either dissociate to yield ionized ethylene or convert into ionized but-2-ene, which undergoes a complete H-exchange prior to dissociation, le ading to methyl radical, hydrogen radical and ethylene losses. The transfer s of labeled atoms and the existence of H-exchange prior to formation of th e products were used as a probe to check the different steps of the mechani sm. The influence of the initial energy of the system on the reaction pathw ay is discussed, Copyright (C) 1999 John Wiley & Sons, Ltd.