Beschreibung:
The gas phase absorption spectra of the compounds OsO4 and RuO4 were measured between 2500 and 1050 Å with a Baird 1−m vacuum monochrometer of 1.0 Å bandwidth. Both tetroxides show many electronic absorption bands in this region with diffuse vibrational structure. No spectra of OsO4 or RuO4 have been previously reported below 2200 Å. Absorption maxima for OsO4, which were not previously reported, occur at 48 140, 63 620, 73 960, 85 620, 86 920, 89 160, 90 800, and 91 940 cm−1. The spectrum of RuO4 showed band maxima at 50 660, 64 620, 72 700, 76 420, 79 040, 83 100, 88 860, and 92 080 cm−1. The general appearance and relative strengths of various absorption bands in the spectra of these molecules were similar, with the energy of apparently corresponding transitions shifted to the red in RuO4 by approximately 10 000 cm−1. Most of the strong electronic transitions have been tentatively assigned on the basis of extended Hückel type calculations. The results of these calculations correlated reasonably well with the spectral data obtained. Bands are present in the spectra of both molecules which may be the first members of Rydberg series.