Negative Fragment Ions from Resonance Capture Processes

Abstract

An examination of negative fragment ions formed by resonance capture processes has been made using a mass spectrometer. It has been found in some cases that the various fragments for a particular molecule arise at the same ionizing energy, possibly by competing decomposition paths from the same state of the negative molecular ion. Other cases where the fragments do not arise at exactly the same energy may be explained by close upper energy states of the negative molecular ion. In general the observed ionization energies are greater than those calculated from the energies of bonds broken and electron affinities. Kinetic energy measurements on some of the more abundant fragments, i.e., Cl⁻ (CCl₄, CH₃·CH₂Cl·CO), O⁻ (SO₂, CO₂, N₂O, NO), show that this excess energy is not translational.