Emission spectrum of SiF 2: Part I. The band system in the region 2755-2179 A

Abstract

The band system in the region 2755-2179 A obtained by exciting flowing SiF 4 vapor is analyzed as due to a non-linear SiF 2 molecule. The vibrational frequencies obtained for the lower electronic state are ν 1 = 778 cm −1, ν 2 = 427 cm −1, and ν 3 = 947 cm −1, while those for the upper electronic state are ν 1 = 597.5 cm −1 and ν 2 = 342 cm −1. From the rotational K-sub-heads observed for four bands, it is shown that the band system belongs to a perpendicular type. The rotational constants obtained from the analysis are C′ = 3.0 cm −1 and C″ = 1.9 cm −1. The following molecular parameters are obtained for the lower electronic state: angle FSiF = 124° ± 2°, and bond lenght SiF = 1.46 ± 0.07 A .