Recent instrumental developments and theoretical speculation have indicated a need for more information concerning the excited electronic states of polyatomic molecules and ions in the elucidation of mass spectra. A theoretical description of these states is necessary for the proper interpretation of existing data and in laying a firm basis for the planning of future experiments. For the above reasons the energies of a number of the excited electronic states of methane have been calculated in a approximate fashion and the results applied to a discussion of the behavior of the methane ion.

There is at present a large collection of data giving the relative abundances of ions formed when molecules, especially hydrocarbons, are bombard with electrons and collected as positives ions in a mass spectrometer. This data per se gives us little insight into the kinetic processes occurring until it is combined with thermodynamic data and subject to a theoretical treatment based upon an assumed model for the kinetic processes taking place in the mass spectrometer. In accordance with our desire to learn more about these kinetic processes and in this way to shed some light on problems of molecular structure we have continued to explore the possible kinetic paths which propane ions take during their decomposition, with special reference to the effect of the substitution of deuterium for hydrogen.

Paths of trip points of Mach reflections produced by 0.5-oz pentolite detonations have been observed for various burst heights. The slopes, Y, at points on the curved path are found to vary from values of Y predicted from plane shock wave data. This discrepancy is attributed to the shock strength conditions at the early inception of the Mach reflection, which later influence the triple point equilibrium, and in lesser degree to radius of curvature effects.

When a one-half ounce spherical charge of high explosive is detonated over a flat plane bounded by a 5 degree incline, the type of phenomenon encountered depends on the distance from ground zero to a beginning of the incline. If this distance is 48" the wave assumes a smooth contour on the plane. Detailed investigation of the shock velocity above the plane reveals that there is a pressure gradient along the shock front for a considerable region which replaces the usual triple point.