Use of translational energy measurements in the evaluation of the energetics for dissociative attachment processes

Abstract

The translational energies of negative ions formed by dissociative resonance capture processes from CO, NO, CO₂, and SO₂ have been measured as functions of excess energy. The sums of the translational energies of O⁻ and the corresponding neutral from CO and NO were found to be equal to the electron energy above onset over a range of about 1 eV. At higher energies, the translational energies dropped down from the expected values because of loss of the more energetic ions to the walls. With CO₂ and SO₂ the total translational energy was always E*/N, where E* is excess energy and N the number of vibrational modes, 3 in each case. The measurement of translational energy has also helped in interpreting the states involved in the various processes and in computing the ground state thermochemical properties of the decomposition products.