Rotation–vibration analysis of the B 0+u–a 1g and B 0+u–a′ 0+g electronic systems of I2 by laser‐induced‐fluorescence Fourier‐transform spectroscopy

The spectrum of fluorescence excited by the 514.5 nm line of a multimode Ar+ laser is recorded by a Fourier‐transform spectrometer. In the region 7000–7300 cm−1 (1.43 to 1.37 μm), transitions from the B 0+u state are recorded into two states, which had been previously only indirectly observed, as well as into the X 1Σ+ state. Vibrational levels 0–9 for the 0+g and 0–14 for the 1g states are sampled. The principal molecular constants determined are as follows: where all constants are in cm−1 except when noted, with 2σ uncertainties in parentheses.