The Electronic Spectrum of Tellurium Dioxide

The electronic spectrum of gas-phase tellurium dioxide has been recorded between 345 and 406 nm using the technique of laser-induced fluorescence spectroscopy. The TeO₂ sample was prepared by direct heating of the solid and by seeding it in a continuous free-jet expansion in argon. Twenty-seven cold bands and thirty-two hot bands were assigned. The wavenumbers of the band origin and symmetric stretching and bending vibrational modes for the upper and lower states were determined in a simple least-squares fit: ν₀ = 25526 cm⁻¹, ω₁^′ = 679 cm⁻¹, ω₂^′ = 220 cm⁻¹, ω₁^″ = 823 cm⁻¹, ω₂^″ = 282 cm⁻¹.