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 Title: High Resolution Infrared Spectra Of The Linear Dialuminum Monoxide Al-o-al Author(s): Döring, Eileen Contributor(s): Fuchs, Guido W; Giesen, Thomas; Gauss, Jürgen; Witsch, Daniel Subject(s): Small molecules Abstract: In the vicinity of evolved stars cosmic dust forms via nucleation processes. Many of the initial steps of nucleation are not well understood but the investigation of small di- and triatomic molecules at radio or infrared wavelengths in these stellar environments can help elucidating the dust formation process. Especially molecules made of refractory material that condense already at temperatures above thousand Kelvin, like aluminum, are thought to act as seed molecules for dust grains. In this work the gas phase spectrum of the symmetric linear dialuminum monoxide Al-O-Al is investigated in our laboratory. Because \chem{Al_2O} has no permanent electric dipole moment it can not be detected at radio wavelengths but it has a unique infrared ro-vibrational spectrum around 10~$\mu$m. We recorded the ro-vibrational absorption spectrum of \chem{Al_2O} by using a frequency modulated quantum cascade laser in combination with Herriott-type multipass optics. The molecules were produced and rotationally cooled down to around 120~K by laser ablating an aluminum rod and purging the resulting ablation plume with a \chem{N_2O}/He buffer gas mixture that subsequently underwent an adiabatic expansion into a vacuum chamber. The spectra reveal a line intensity alteration due to the spin-statistical weight induced by two identical spin 5/2 $^{27}$Al atoms. The fundamental $\nu_{3}$= 1-0 as well as five hot band transitions could be observed. Highly precise molecular constants could be determined and a l-type resonance was analyzed. The here presented transition frequencies will allow for astrophysical searches of this molecule in space. Issue Date: 2021-06-25 Publisher: International Symposium on Molecular Spectroscopy Genre: Conference Paper / Presentation Type: Text Language: English URI: http://hdl.handle.net/2142/111166 Date Available in IDEALS: 2021-09-24
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