The spectrum of SiO in the vacuum ultraviolet region

The absorption spectrum of SiO has been photographed at high resolution in the region 1200–1500 Å. Several new electronic states have been observed, valence states as well as Rydberg states. Tables of the molecular constants of all the known states of SiO are given. Due to interactions between the electronic states, the constants of all states analyzed vary irregularly. From the Rydberg series a value of the ionization potential has been derived. It agrees with the value earlier reported, 11.6 ± 0.2 eV.