Near infrared laser spectroscopy of ScI: The C1Σ+–X1Σ+ transition

The C1Σ+–X1Σ+ electronic transition of scandium monoiodide (ScI) between 790 and 850 nm has been studied using laser vaporization/reaction free jet expansion and laser induced fluorescence spectroscopy. Twelve vibrational (v′, v″) bands with v′ = 0–2 and v″ = 0–6 have been recorded and analyzed. A merged least squares fit of the measured line positions yielded accurate molecular constants for both the C1Σ+ and X1Σ+ states. The perturbation found in the (0, 2) band of this transition confirmed that v = 2 level of the X1Σ+ state is perturbed.