Direct evaluation of the asymmetry parameters for isolated resonances

We employ an efficient procedure based on second-order perturbation theory to obtain the asymmetry parameters of isolated resonances without computing the spectra. We show that this method gives values of the asymmetry parameters of the predissociating resonances corresponding to the vibrational levels of the Cs 2 molecule that are in good agreement with those obtained by fitting the spectra. We also show the onset of overlapping between the resonances by computing the asymmetry parameters at several increasing values of the spin-orbit coupling between the discrete and continuum states.