Reinvestigation of the second negative (A²Π_u-X²Π_g) band system of O₂⁺

Abstract

The A²Π_u state of O₂⁺ was earlier established as an inverted state contrary to previous assumptions. The rotational analysis of a few more bands of the A-X system of O₂⁺ has now been completed. These studies show that the spin-orbit coupling constant A in the A²Π_u state gradually varies with the vibrational quantum number ν and is found to be positive for ν≥6. It has also been observed that the spia-rotation interaction is not negligible in the A ² Π_u state. The spin splitting constant γ is reported for various vibrational levels of this electronic state.