University of Illinois Urbana-Champaign

Completion Of The First Solvation Shell Of Carbon Dioxide In Argon: Rotationally Resolved Infrared Spectra Of Co2-ar15 And Co2-ar17

Moazzen-Ahmadi, Nasser

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https://hdl.handle.net/2142/116833

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Title
Completion Of The First Solvation Shell Of Carbon Dioxide In Argon: Rotationally Resolved Infrared Spectra Of Co2-ar15 And Co2-ar17
Author(s)
Moazzen-Ahmadi, Nasser
Contributor(s)
  • Barclay, A. J.
  • McKellar, A.R.W.
Issue Date
2022-06-23
Keyword(s)
Mini-symposium: Benchmarking in Spectroscopy
Abstract
There have been a number of theoretical papers on the structures and energetics of CO$_2$-Ar$_n$ clusters. But in terms of experiment, the only previous spectroscopic results are for n = 1 (extensive work on the CO$_2$-Ar dimer) and n = 2 (microwave and infrared spectra of CO$_2$-Ar$_2$). We have now obtained and analyzed infrared spectra in the CO$_2$ $\nu_3$ region for a number of clusters in the range n = 3 to 17. Notable among these are CO$_2$-Ar$_{15}$ and CO$_2$-Ar$_{17}$, which mark completion of the first solvation shell for CO$_2$ in argon. These clusters have highly symmetric structures with D$_{3h}$ and D$_{5h}$ symmetry, respectively, in good agreement with theory. For n = 15, CO$_2$ is surrounded by five argon rings, each containing three Ar atoms. For n = 17, there are three rings of five atoms each, plus two additional Ar atoms located on the symmetry axis at each end. The observed spectra are symmetric top parallel bands, and both exhibit distinct intensity alternation which helps to confirm their assignment. Observed B-values are 69.93 MHz for CO$_2$-Ar$_{15}$ and 54.52 MHz for CO$_2$-Ar$_{17}$. As usual for symmetric rotors, the spectra are not sensitive to the A constant, but we do obtain precise values for the band origins, and hence the vibrational shifts (relative to free CO$_2$) as induced by the argon cages.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Handle URL
https://hdl.handle.net/2142/116833
DOI
https://doi.org/10.15278/isms.2022.RI09
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Copyright 2022 held by the authors

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Abstracts & Presentations - 2022 International Symposium on Molecular Spectroscopy PRIMARY