Rotational and vibrational temperatures of BaO from a barium release at 170 km, and the synthetic spectrum of BaO in the region 4700 Å to 15,500 Å

Band spectra of BaO covering a total wavelength region of 5050 Å-9300 Å were recorded from the ground with a scanning spectrophotometer at 7.1 Å resolution during a series of barium rocket releases at College, Alaska in the Spring of 1969. Rotational and vibrational temperatures, both equal to approximately 850°K at the release altitude of 170 km, were inferred by matching the release spectra with calculated synthetic spectra. This temperature persisted throughout the observing period, from release + 20 sec to 14 min after release.

Analysis of the BaO band spectrum over a large wavelength region reveals that rotational temperatures are best determined at wavelengths below 5500 Å, and that vibrational temperatures should be measured at wavelengths greater than 5500 Å. Comparisons with synthetic spectra show that several broad emission features in the release spectra, located at about 7900 Å 8400 Å and 9000 Å, may be identified as clusters of overlapping BaO bands. A synthetic spectrum of BaO extending from 4700 Å to 15,000 Å is included for general reference and to facilitate future studies in that wavelength region.