Charge transfer transitions of the O2+–Ar and O2+–N2 complexes

Abstract

Electronic transitions are observed for the O2+–Ar and O2+–N2 complexes over the 225–350 nm range. The transitions are not associated with recognized electronic band systems of the respective atomic and diatomic constituents (Ar+, Ar, O2+, O2, N2+, and N2) but rather are due to charge transfer transitions. Onsets of the O2+–Ar and O2+–N2 band systems occur at 3.68 and 3.62 eV, respectively, corresponding to the difference in the ionization potentials of Ar and O2 (3.69 eV), and N2 and of O2 (3.51 eV), suggesting the band systems arise from intramolecular charge transfer transitions to states correlating with O2(X3Σg−) + Ar+ (2Pu) and O2(X3Σg−) + N2+(X2Σg+) limits, respectively. The dominant vibronic progressions have ωe values of 1565 cm−1 for O2+–Ar and 1532 cm−1 for O2+–N2, reasonably close to the value for the neutral O2  molecule in its X3Σg− state (1580 cm−1). Higher energy band systems for O2+–Ar and O2+–N2 are assigned to transitions to states correlating with the O2 (a1Δg) + Ar+ (2Pu) and O2 (a1Δg) + N2+(X2Σg+) limits, respectively.