Transition strengths in the visible–infrared absorption spectrum of I2

The contributions of the 1Πu←X, B←X, and A←X transitions to the absorption coefficient of I2 in the 4200–8000 Å region are reassessed in light of recent results concerning the 1Πu and A potentials and their diffuse absorption spectra. Earlier estimates of the continuum underlying the B←X discrete spectrum are augmented by additional high-resolution ’’between-the-lines’’ absorption measurements, corrected for residual B–X absorption using the very reliable spectroscopic constants now available for this system. The 1Πu–X and A–X systems are now estimated to be about 10% weaker than in the previous analysis [J. Tellinghuisen J. Chem. Phys. 58, 2821 (1973)]. For the region 2.6–2.8 Å sampled in absorption, the estimates of the B–X transition strength ‖μe‖2 remain close to the previous values.