Laser spectroscopy of YI: rotational analysis of the C1Σ+–X1Σ+ system

The (v′, v″) bands of the C1Σ+–X1Σ+ transition of YI with v′=0–7 and v″=0–4 between 769.2–843.7 nm have been studied using the technique of laser vaporization/reaction with supersonic cooling and laser induced fluorescence spectroscopy. Sixteen vibronic transition bands have been observed and analyzed. A merged least squares fit of the measured line positions yielded molecular constants for both the C1Σ+ and X1Σ+ states. The equilibrium bond length of the C1Σ+ and X1Σ+ states has been determined to be 2.8280(2) and 2.7637(3) Å, respectively.