Spectra attributed to transitions from the 5sσ α 3Σu+ metastable state of Kr2 to excited Rydberg states have been observed by intracavity and multipass absorption and by laser excitation spectroscopy. Four distinct Rydberg series converging on the X 2Σu+ core of Kr 2+ have been identified. Rotational structure is not resolved in any of the observed spectra. Most of the spectra can be assigned to vibronic transitions in the nfλ(3Σg, 3Σg+) and npλ(3Σ g,3Σg+)←a 3Σu+ series by analogy with similar spectra in the lighter rare gas dimers. The 6pπ 3IIΠ g←a 3Σu+ and 8pσ 3Σg+ ←a 3Σu + transitions observed in the ∼19 200 - 18 200 cm-1 region exhibit many bands with v′≠0 in their (v′-v″) vibrational band system developments. The higher n value members of these and other observed series are dominated by (0 - 0) transitions. All series are perturbed in a few energy regions by states built on the excited ion core states A 2Π3/2g and B 2Π3/2u. Laser excitation spectra for the 8pσ 3Σg+ ←a transition obtained by monitoring various 5p→5s emission lines of atomic krypton suggest that the 8pσ 3Σg + Rydberg state of Kr2 is predissociated by a repulsive potential correlated with Kr 5p[3/2]1+Kr(1S0). The lowest ionization limit of Kr2 (relative to a 3Σu+,v=0) was determined to be 28 484±5 cm-1.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry