Drs. John Moore and John Tossel from University of Maryland, and Dr. Judith Giordan, an employee of Aluminum Company of America are supported by a grant from The Physical Chemistry Program to study various aspects of the interaction of low energy electrons with gas phase molecules. An improved understanding of physical processes of this type has important commercial implications in the plasma etching and plasma deposition industry. Moore and coworkers are studing three separate aspects of electron molecule interactions. Electron Transmission Spectroscopy (ETS) is being used to study the low lying unoccupied molecular orbital energy levels (LUMO's) which are of fundamental importance in explaining pi bonding and chemical reactivity. This research group has also recently modified their basic ETS instrument to make measurements of total inelastic cross sections for electron scattering. Measurements which have required many painstaking hours to collect in other laboratories are now possible to obtain in about 30 seconds using only a slight modification of the original instrument. Inner Shell Electron Energy Loss Spectroscopy (ISEELS) is being used to study the lowest lying unoccupied molecular orbitals of the molecular cation. ISEELS involves the trapping of knocked-out inner shell electrons in the valence region of the molecular energy levels. Moore and coworkers have found a definite and chemically important correlation between the results of the ETS and ISEELS spectra. New experiments are also being conducted in the area of free radical reactions. Moore and coworkers have found that they can produce reasonably intense molecular beams of neutral free radicals by dissociative electron attachment followed by removal of the charged anionic fragmentation products. They plan to study the reactions of the product free radicals with various target gasses.
