The absolute cross sections of all the possible dissociation channels following the electron-impact multiple ionization of CO have been measured. The cross sections of the channels corresponding to the production of ion pairs are measured by coincidence techniques. Those of the channels associated with neutral fragments are obtained indirectly. At high excitation energies, the total cross sections of different stages of ionization show an exponential decrease as the ionization stage increases. The cross sections of different channels reveal the internal dissociation dynamics of the dissociation following the multiple ionization of the molecules. The appearance potentials corresponding to different dissociation channels are also measured, which show that the ground states of triply and quadruply ionized CO are nearly Coulomb-like because the Coulomb interactions inside the molecules are stronger.

• Received 23 September 1998

DOI:https://doi.org/10.1103/PhysRevA.59.1955