Polarized fluorescence of jet-cooled molecular iodine

The degree of polarized fluorescence of molecular iodine 127I2 cooled in a supersonic jet under rotationally selective excitation in the electronic transition B3Π0u+-X1Σg+ has been measured and calculated. It was found that the interaction of the angular momentum of the molecule with the nuclear spins of iodine atoms leads to a considerable depolarizing effect. This effect is most pronounced for small rotational quantum numbers of the angular momentum that are comparable with the total nuclear spin of the iodine molecule, which is equal to 5.