Gerade Rydberg states of Xe2 probed by laser spectroscopy in the afterglow of a Xe microplasma: transitions in the near-infrared (675–800 nm)

Gerade Rydberg states of Xe2 lying 12 500–14 800 cm−1 above the a 3 Σ u + ( 1 u , O u - ) metastable levels of the dimer have been observed by laser spectroscopy in the afterglow of a Xe microplasma with a volume of ∼160 nL. Photoexcitation of Ω g ← a 3 Σ u + ( 1 u , O u - ) (Rydberg ← Rydberg) state transitions at small internuclear separations ( R ≃ R e ( Xe 2 + ) ) while monitoring the suppression of Xe 2 ( O u + → O g + ) spontaneous emission in the ultraviolet confirms the presence of an extensive series of red-degraded vibrational bands in the 675–800 nm region that are tentatively identified with an Ω = 1 upper state with a molecular ion core having predominantly B2Π3/2g character. Spectral simulations yield the following constants for the 1g state: R e ′ = 3.49 ± 0.1 Å , Te = 12 980 ± 70 cm−1, ω e ′ = 122 ± 3 cm−1, ω e ′ x e ′ = 0.9 ± 0.2 cm−1, and D e ′ = 2250 ± 70 cm−1.