J. William McConkey

Selective detection of O(1S) and CO (a3Π) following electron impact on CO using solid xenon

Abstract The neutral metastable species O(1S) and CO(a3Π) produce distinctly different red and UV emissions respectively within a few microseconds of their impact on a surface of solid Xe. This effect has been employed as a novel means of detection in a crossed beam experiment to obtain time-of-flight (TOF) spectra and relative cross sections of both species following electron impact on carbon monoxide. TOF spectra of O(1S) show five possible dissociation channels. Semi-quantitative partial potential curves were constructed for the parent molecular states of two of those channels. The relative cross section for O(1S) production was made absolute by comparison with production of the same from O2. The cross section reaches a maximum of 5×10−19 cm2 at 100 eV. The relative cross section for CO(a3Π) production includes cascade from the higher triplet states of CO and is uncontaminated by the 10 e V metastable state of CO.

Chapter One – Detection of Metastable Atoms and Molecules using Rare Gas Matrices

Abstract The use of rare gas matrices for the detection of a variety of low-energy metastable species, particularly those from atoms with an np 4 outer electron configuration, is discussed in detail. The historical development of the detector is outlined and its performance as a function of rare gas, matrix temperature, and metastable species is discussed. Examples of its use are given for electron impact dissociation of a wide variety of oxygen and sulfur containing targets.

O(1S) production following electron impact dissociative excitation of NO

Solid Xe was used to detect oxygen atoms in the 1S metastable state following their production by electron impact on nitric oxide. Time-of-flight spectra of O(1S) for several electron impact energies were obtained. The repulsive portion of the potential curve for one of the parent states of NO which led to O(1S) was deduced from the data.