Ion-molecule reactions studied at non-zero scattering angles in a mass spectrometer

A method is described by which ion-molecule reactions which involve non-zero scattering angles can be studied in a double-focusing mass spectrometer. Reactions in which there is no alteration in the charge on the reactant ion, while the target species is ionized or excited, have been examined at relative translational energies of 1-10 keV. The method allows the measurement of kinetic energy losses.Interference due to the main beam of non-reacting or elastically scattered ions is minimized relative to the zero scattering angle case. In addition to applications for the determination of ionization potentials and other quantities of thermochemical interest, it is suggested that the study of collisional excitation might be facilitated.