No abstract

Calculated oxygen absorption coefficients are given for the spectral range 180–300 nm, at a spectral resolution of 0.05 nm (instrumental function half-width) and with a spectral increment of 0.0125 nm. The results are presented for temperatures between 300 and 3000 K, and for pressures between 1 and 50 atm. The spectra were first calculated at high resolution, preserving the natural shape of the spectral lines, using line-by-line techniques and Voigt line shapes. Absorption processes considered include the Schumann–Runge and Herzberg 1 band and continuum systems, including the pressure-dependent component usually ascribed to the formation of the (O2)2 dimer. The results were degraded before use, which allowed several approximations to be introduced into the computing procedures; these are discussed.

Mixtures of ammonia in xenon were shock heated to temperatures in the range 2900° to 9600°K and the radiation from NH was monitored at 3360 Å. It was found that the production of NH (A3II) was second order in initial ammonia concentration within experimental error, and could be described by a rate constant K=4×10—14 exp ( —54 000/T) cm3 molecule—1·sec—1. Significant changes in shape of the radiation profiles were observed at different temperatures; in particular it was found that NH normally decayed at two different rates, one being half as great as the other. The results are discussed and compared with recent measurements made by other authors, revealing some discrepancies that could not be explained.

The different kinds of light sources available for the 0.15-20-micro spectral range are surveyed. Information was obtained from the published literature, unpublished reports, light source manufacturers, and also from individual persons. The aim has been to present sufficient information, where available, to show the relative advantages of different sources-intensity, stability, and output uniformity were of prime interest. Continuum and line sources are included but lasers and pulsed sources are omitted. The sources are described under the main headings: Arc Discharge Sources, Glow Discharge Sources, and Incandescent Sources, with another section, Miscellaneous Sources, to cover some which could not be included under the first three headings.