Spectra of Rg-water dimers in the region of the D₂O ν₃ asymmetric stretch (Rg = Ar, Kr, Xe)

Abstract

Spectra of rare gas (Rg) – D₂O dimers (Rg = Ar, Kr, Xe) are studied in the region of the D₂O ν₃ 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.

GRAPHICAL ABSTRACT

KEYWORDS:

• Water rare gas clusters
• infrared
• vibrational bands
• optical parametric oscillator
• spectra

Acknowledgements

The financial support of the Natural Sciences and Engineering Research Council of Canada is gratefully acknowledged. C.L. and R.G. acknowledge the financial support of the FNRS through CDRs J.0129.20 and J.0113.23 and of the Fédération Wallonie-Bruxelles through the Action de Recherches Concertées (grant number ARC iBEAM-18/23-090). R.G. is a FRIA grantee of the Fonds de la Recherche Scientifique (FNRS).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplementary Material includes tables giving observed and fitted line positions for Ar-, Kr-, and Xe-D₂O, and detailed isotopic dependence of molecular parameters for D₂O-Kr.

Additional information

Funding

The financial support of the Natural Sciences and Engineering Research Council of Canada is gratefully acknowledged. C.L. and R.G. acknowledge the financial support of the FNRS through CDRs J.0129.20 and J.0113.23 and of the Fédération Wallonie-Bruxelles through the Action de Recherches Concertées (grant number ARC iBEAM-18/23-090). R.G. is a FRIA grantee of the Fonds de la Recherche Scientifique (FNRS).