ON THE DETERMINATION OF A HETEROGENEOUS VS A HOMOGENEOUS PERTURBATION IN THE SPECTRUM OF A DIATOMIC MOLECULE - THE KAPPA(1)SIGMA(+), UPSILON = 0 STATE OF (CO)-C-13-O-18

A spectrum of the K1Σ+, v = 0 state of 13C18O, excited by XUV-laser radiation, has been recorded. It turns Out to he an exemplary case of a strongly perturbed rotational manifold without direct spectroscopic information on the perturber state. The question of the nature of a perturbation, i.e., whether it is heterogeneous or homogeneous, is addressed. From a numerical analysis it follows that the perturbation of the K1Σ+, v = 0 state is heterogeneous and that the perturber may he tentatively identified as the E1Π, v = 5 state. Precise values for the molecular constants are determined for both the K1Σ+v, v = 0 and the perturber state. © 1994 Academic Press, Inc.