B3Π0 +u—X1∑ +g systems of 127I2 and 129I2. Molecular constants, laser-excited fluorescence and Franck–Condon factors

Abstract

Rotational distortion constants for the B³ΠO⁺_u and X¹∑⁺_g states of ¹²⁷I₂ have been computed from the RKR potentials according to the method of Albritton et al. Vibrational and rotational constants in the range 0 ⩽ν⩽ 77 have also been estimated for the B state of ¹²⁹I₂. The present results together with the constants of Barrow and Yee are used to identify and assign all the main laser-excited molecular transitions observed in the B–X systems of ¹²⁷I₂ and ¹²⁹I₂. Extensive matrices of Franck–Condon factors for both isotopes have been calculated, and the computed relative intensities are consistent with the known resonance fluorescence series.