Diode laser spectroscopy of the BO2 radical: The transition of the ν2 fundamental band

The (0, 1, 0)κ 2 Σ ← (0, 0, 0) 2 Π 3 2 vibration-rotation transition of BO 2 has been observed by infrared diode laser spectroscopy. The observed wavenumbers were combined with the spectral data on the (0, 1, 1) ← (0, 1, 0) band previously reported and were analyzed by the least-squares method to yield the ν 2 -band origin 633.8049(9) cm −1 and the spin uncoupling constants γ κ = 0.167 38(19) and 0.153 48(17) cm −1 , respectively, for the (0, 1, 1) κ 2 Σ and (0, 1, 0) κ 2 Σ states, with three standard deviations in parentheses. The effects of rovibronic interaction on the spin uncoupling constant and its centrifugal distortion correction term have been discussed in some detail. It has been found that the (0, 1, 1) κ 2 Σ state is perturbed by the (1, 2, 0)μ 2 Π 3 2 state through higher order rovibronic interaction.