[en] The detailed rotational analyses for the E1 bands of the dihydrides and deuterides of Se and Te recorded in a high-resolution photoabsorption experiment, using synchrotron radiation, are presented. This provides one with the symmetry species and effective rotational constants of the excited states. Discrepancies in the intensities of the lines between the observed and theoretical spectra, reveal effects due to homogeneous and heterogeneous predissociation and l uncoupling. (author)