RESEARCH ARTICLE Theoretical spectroscopic study of acetyl (CH 3 CO), vinoxy (CH 2 CHO), and 1-methylvinoxy (CH 3 COCH 2 ) radicals. Barrierless formation processes of acetone in the gas phase [version 1; peer review: awaiting peer review] Hamza El Hadki 1 , Victoria Guadalupe Gámez 2 , Samira Dalbouha 1,3 , Khadija Marakchi 1 , Oum Keltoum Kabbaj 1 , Najia Komiha 1 , Miguel Carvajal 4,5 , Maria Luisa Senent Diez 2 1 Laboratoire de Spectroscopie, Modélisation Moléculaire, Matériaux, Nanomatériaux, Eau et Environnement, LS3MN2E/CERNE2D, Faculté des Sciences Rabat, Université Mohammed V, Rabat, BP1014, Morocco 2 Departamento de Química y Física Teóricas, IEM-CSIC, Unidad Asociada GIFMAN, CSIC-UHU, Madrid, 28006, Spain 3 Equipe de recherche : Matériaux et Applications Environnementales, Laboratoire de Chimie Appliquée et Environnement, Département de chimie, Faculté des Sciences d’Agadir, Université Ibn Zohr, Agadir, B.P 8106, Morocco 4 Departamento de Ciencias Integradas, Centro de Estudios Avanzados en Física, Matemática y Computación; Unidad Asociada GIFMAN, CSIC-UHU, Universidad de Huelva, Huelva, 21071, Spain 5 Instituto Universitario Carlos I de Física Teórica y Computacional, University of Granada, Granada, Spain First published: 30 Sep 2021, 1:116 https://doi.org/10.12688/openreseurope.14073.1 Latest published: 30 Sep 2021, 1:116 https://doi.org/10.12688/openreseurope.14073.1 v1 Abstract Background: Acetone is present in the earth´s atmosphere and extra- terrestrially. The knowledge of its chemical history in these environments represents a challenge with important implications for global tropospheric chemistry and astrochemistry. The results of a search for efficient barrierless pathways producing acetone from radicals in the gas phase are described in this paper. The spectroscopic properties of radicals needed for their experimental detection are provided. Methods: The reactants were acetone fragments of low stability and small species containing C, O and H atoms. Two exergonic bimolecular addition reactions involving the radicals CH 3 , CH 3 CO, and CH 3 COCH 2 , were found to be competitive according to the kinetic rates calculated at different temperatures. An extensive spectroscopic study of the radicals CH 3 COCH 2 and CH 3 CO, as well as the CH 2 CHO isomer, was performed. Rovibrational parameters, anharmonic vibrational transitions, and excitations to the low-lying excited states are provided. For this purpose, RCCSD(T)-F12 and MRCI/CASSCF calculations were performed. In addition, since all the species presented non-rigid properties, a variational procedure of reduced dimensionality was employed to explore the far infrared region. Open Peer Review Reviewer Status AWAITING PEER REVIEW Any reports and responses or comments on the article can be found at the end of the article. Open Research Europe Page 1 of 23 Open Research Europe 2021, 1:116 Last updated: 30 SEP 2021