Excitation spectra of the 5s 3Σu+ (1u,0u-) state of the Kr2 molecule have been obtained in the wavelength interval 335≤λ ≲ 545 nm by monitoring atomic Kr emission at 758.7 nm (5p[1/2]0→5s[3/2] 1) that accompanies dye laser excitation of the neutral excited molecule. The dominant peaks in the spectrum are identified as arising from np 3Πg ←5s 3Σu + Rydberg transitions where 7≤n≤18. The series limit and quantum defect δ for this series have been determined to be 28 471.9±3.9 cm-1 (351.12±0.05 nm) and 2.629±0.004, respectively, and the vibrational frequency ωe of the 5s 3Σu+ (1u,0u -) excimer has been estimated to be ∼195 cm-1. All of the observed Rydberg states have an A 2Σ1/2u +[1(1/2)u] ion core. Comparison of the np 3Πg→5s 3Σu+ series limit and the ionization potential of Kr* 5s[3/2]2 shows that the A 2Σ1/2u+ ground state dimer ion is ∼0.55 eV more deeply bound than is the Kr2 5s 3Σu+ neutral species. Also, dissociation energies of the np 3Πg Rydbergs are shown to be nearly identical to that of the A 2Σ1/2u+ dimer ion state. A second series of spectral peaks has also been identified and assigned to n′ 3Σg+←5s 3Σu+ transitions. Analysis of the series yielded a limit of 28 424±120 cm-1 and a quantum defect of 3.39±0.04. Two members of a third, unidentified series having a quantum defect of 3.24±0.01 and also converging to A 2Σ 1/2u+ (v′=0) have been observed. Absolute photoabsorption cross sections for the np 3Πg←5s 3Σu+ (7≤n≤18) transitions have also been determined.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry