Rotational analysis of electronic bands of gaseous TaO

Abstract

The rotational analysis of a number of bands in the emission spectrum of the arc in air between Ta rods in the region 2740–9500 Å has been completed. In all, 19 different electronic states, or substates, have been characterized : perturbations indicate the presence of others. Comparison with the absorption spectrum of matrix isolated TaO shows that the ground state X₁ of TaO has Ω= 3/2. X₁ is the lower state of many of the emission bands. A second lower state X₂ with Ω= 5/2 lies at 3505 cm^–1 above X₁. If case a is followed, the ground state of TaO is therefore ²Δ with constants (cm^–1) as follows [graphic omitted] A few bands with ΔΛ or ΔΩ=±1 in this spectrum have upper and lower states numbered by integral, rather than half-integral, values of J. These bands do not appear in the Ta arc in nitrogen, and it is suggested that they arise from a transition in TaO⁺.