Cross Sections of Ion—Permanent-Dipole Reactions by Mass Spectrometry

Abstract

Proton transfer is the most probable type of reaction observed in a number of ion—molecule interactions involving permanent dipoles. Integrated cross sections, which are unusually large, are described in terms of an ion—dipole pair oriented near the position of minimum energy at low relative velocity. As the relative velocity is increased, this alignment becomes less likely. The energy-dependent cross section is eclipsed at high relative velocity by the ``hard'' cross section which does not vary with energy. Proton affinities are estimated for several alkyl cyanides. Some of the reported reactions appear to involve excited states of the primary ions.