Ionization and Dissociation of Diatomic Molecules by Electron Impact

TLDR

The study extends mass spectrometry to investigate ionization and dissociation of diatomic molecules (H₂, CO, NO, N₂, O₂) under electron impact. Peak shapes in resolved ion current versus accelerating potential were analyzed using wave‑mechanical theory and mass‑spectrometer characteristics, enabling conclusions about dissociation mechanisms and molecular structure. The work reconciles discrepancies with earlier data, provides refined dissociation energies and ionization potentials, and offers interpretations of the observed processes.

Abstract

An extension of the mass spectrometric method of study of ionization and dissociation processes occurring in diatomic molecules under electron impact and the results of further investigation of the molecules ${\mathrm{H}}_{2}$, CO, NO, ${\mathrm{N}}_{2}$, and ${\mathrm{O}}_{2}$ are discussed. The shapes of the peaks which appear in the graph of resolved ion current as a function of ion accelerating potential are analyzed and accounted for in terms of the wave-mechanical theory of the diatomic molecule and the characteristics of the mass spectrometer. It is indicated how the study of the peak shape coupled with appearance potential measurements has made possible conclusions concerning the nature of the dissociation process and the structure of the molecule. Differences between previous mass spectrometric data and those from other sources have been clarified either by obtaining better data with the mass spectrometer or by formulation of a satisfactory interpretation of the difference based on conclusions of an analysis of the ion peak shape. Values of dissociation energies, ionization potentials and interpretations of the processes that occur are given.