Spectroscopy of TaO

Abstract

Emission bands of TaO between 7000 and 28 000 cm−1 were recorded with FTS techniques using an electrodeless 2450-MHz discharge and an on-line monitoring MES spectrometer. Transitions involving 14 electronic substates combining with the X2Δ ground state were analyzed. One of these states was not reported earlier. Three of these 14 states have transitions to both sublevels of the ground state, hence the ground state (a regular 2Δ state) parameters were not only improved, but we also for the first time applied a Hund's case (a) description to it. In addition to these states, two additional states were analyzed from a previously unreported band at ∼10 000 cm−1; neither of these states combines with either the ground state or with the 14 excited states of this work. It was assumed that a 2Σ state is involved in this transition. An interesting feature in this work is a local perturbation in the P′ state. The term value representation of the perturbation shows a derivativelike shape with normal (unperturbed) intensity variation around the center of the perturbation. A three-level interaction scheme was used to model this perturbation.