| Abstract | Spectra of rare gas (Rg) – D₂O dimers (Rg = Ar, Kr, Xe) are studied in the region of the D₂Oν₃ asymmetric stretch (≈2800 cm⁻¹), using a rapid-scan tunable infrared optical parametric oscillator source to probe a pulsed supersonic slit jet expansion. Three bands are observed in each case, labelled according to the D₂O rotational transition with which they correlate as: Σ(1₀₁) ← Σ(0₀₀), Π(101) ← Σ(0₀₀), and Σ(0₀₀) ← Σ(1₀₁). The Ar-D₂O bands exhibit various perturbations and line broadening effects. For Kr-D₂O, the Π(101) ← Σ(0₀₀) and Σ(0₀₀) ← Σ(1₀₁) bands are simple and relatively unperturbed with almost no resolved Kr isotope structure, while the Σ(1₀₁) ← Σ(0₀₀) band is highly perturbed and shows large isotope splittings. This latter perturbation is analyzed in detail with good results. For Xe-D₂O, the experimental spectra are unfortunately weaker. Analysis of the Π(101) ← Σ(0₀₀) and Σ(0₀₀) ← Σ(1₀₁) bands is again relatively straightforward, but the Σ(1₀₁) ← Σ(0₀₀) band is even more perturbed than for Kr-D₂O and its analysis proves impossible. Line broadening (for Ar-D₂O) and vibrational frequency shift effects are described. |
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