AlOSO: Spectroscopy and Structure of a New Group of Astrochemical Molecules

Abstract With the ever-increasing detection of sulfur-bearing molecules and high abundance refractory nature aluminum, [Al, S, O 2 ] isomers may play an important role in gas-phase chemistry circumstellar envelopes on surface dust grains. High-level theoretical exploration molecular system yielded five isomers, predictions their rotational, vibrational, electronic spectroscopic properties are provided to inform experimental observational searches. Cis-AlOSO diamond isoenergetic connected via a very small (∼1 kcal mol −1 ) transition-state barrier. These act as intermediates along chemical pathway between Al + SO AlO SO. Other OAlOS SAlO stable relative corresponding dissociation asymptotes. Large permanent dipole moments 2.521 D (cis-AlOSO), 1.239 (diamond), 5.401 (OAlOS) predict strong rotational transitions indicate these prime candidates for study. Due low barrier, mixing vibrational levels is anticipated, complicating spectrum. Electronic spectroscopy be used means differentiate two isomers. Strong predicted occur 200–300 nm range cis-AlOSO diamond. Simulated absorption spectra provide starting point characterization spectral deconvolution