title: The triplet states of butadiene and benzene by He+ impact
authors: Kenichi Iwamoto and Akira Matsumoto
affiliations: Materials Science, College of Integrated Arts and Sciences,
Osaka Prefecture University, Japan 
summary: The excited electronic states of trans-1,3-butadiene and benzene
by He+ impact were measured with the ion energy loss spectrometer equipped
with the Matsuda plate. Two triplet states of butadiene were observed. The
spectrum of benzene was obtained by separating of the first and second
triplet states. These excitation energies were in good agreement with the
results of the electron-energy loss experiments.