Description of the absorption spectrum of iodine recorded by means of Fourier Transform Spectroscopy : the (B-X) system

An in extenso analysis of the (B-X) I2 iodine absorption spectrum recorded by means of Fourier Transform Spectroscopy is presented. It is shown that the 100 000 recorded transitions covering the 11 000-20 040 cm-1 range and published in several Atlases may be recalculated by means of only 46 constants : 45 are Dunham coefficients describing the vibrational and rotational constants of both X state (up to v" = 19) and B state (up to v' = 80, situated only at 1.6 cm-1 from the dissociation limit of the B state), and one empirical scaling factor which takes account of neglected centrifugal constants higher than Mv. The overall standard error between computed and measured wavenumbers is equal to 0.002 cm -1 in agreement with the differences of numerous independent absolute wavenumbers and the computed ones.