SPIN-ORBIT INTERACTIONS BETWEEN RYDBERG STATES OF O-2

Spin-orbit interactions between Rydberg states of O-2 have been studie d by observing the photoabsorption spectrum in the 1100 - 1200 Angstro m region. The dominant interactions are between states having the same primary molecular orbital configuration and these give rise to pertur bations in rotational-level structures and the appearance of nominally -forbidden absorption bands. Three examples are given showing the effe cts of (3) Pi(u) - (1) Pi(u) and (3) Sigma(u)(+) - (3) Sigma(u)(-) int eractions in the ground-state absorption spectrum.