Predissociation lifetimes of the rotational and fine structure levels of O2+(b4Σ−g, v=3,4,5)

Abstract

A fast ion beam coaxial with a single mode laser has been used to measure the absorption linewidths of predissociated levels of O⁺₂(b⁴Σ_g⁻, v=3,4,5) by detection of the O⁺ photofragments. Tuning of the absorption wavelength was accomplished by a combination of intracavity etalons and variation of the ion beam velocity (Doppler tuning). Lifetimes were determined for the b state fine structure levels of rotational levels N=31 and 33 of ¹⁶O₂⁺(v=3), N=9–25 of ¹⁶O₂⁺(v=4), N=14–27 of ^16,18O₂⁺(v=4), and N=5–7 of ¹⁶O₂⁺(v=5). The lifetimes vary from 0.06 to 4 nsec. Variation with all relevant quantum numbers and with isotopic composition is discussed.