Energy redistribution in the dissociation of low Rydberg states of HeH and 02

In this thesis the dissocation process is studied of the diatomic molecules, heliumhydride and molecular oxygen. In ch.'s 2-4 results on the spectroscopy and dissociative decay of the excited states of heliumhydride (HeH) are explained. The positions and dissociation pathways of the A2Σ+ and B2Π states are determined and a theoretical description of the decay of these states are given. An isotope dependent dissociation behaviour of the C2/σ+ Rydberg state is reported which explained with this theory. In ch.'s 5-7 observations are presented regarding the first Rydberg states of molecular oxygen. The spectroscopy of the (3sσ)d 1Πg and C3Πg states is treated, and the stability and decay of these Rydberg states is discussed qualitatively. An experimental study is described of the (3sσ)d 1Πg , v=4-8 states. By isotope studies and resolving rotational lines and the measurements of natural linewidths quantitative estimates have been acquired on coupling strengths, positions of repulsive valence states and perturbations reported in literature from REMPI experiments. The electronic coupling strengths between the C3Πg state and the 3Πg valence state has been established. Observed spin-orbit interactions have been quantified and the dissociation of the multiplet states (C3Πg,ω=0-2 has been correlated with the multiplet states of the fragment O3P J=0-2. The spectroscopy of the (3sσ3) Rydberg states which con- verge to and are formed in collisions with the O+2, a4Π μ ion state, is treated. The (3sσ)5/π μ state competition between auto-ionizations and (pre-)dissociation has been observed. 207 refs.; 36 figs.; 18 tabs