https://insu.hal.science/insu-03691535Faure, AlexandreAlexandreFaureIPAG - Institut de Planétologie et d'Astrophysique de Grenoble - INSU - CNRS - Institut national des sciences de l'Univers - CNES - Centre National d'Études Spatiales [Toulouse] - CNRS - Centre National de la Recherche Scientifique - OSUG - Observatoire des Sciences de l'Univers de Grenoble - Grenoble INP - Institut polytechnique de Grenoble - Grenoble Institute of Technology - INSU - CNRS - Institut national des sciences de l'Univers - IRSTEA - Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture - USMB [Université de Savoie] [Université de Chambéry] - Université Savoie Mont Blanc - CNRS - Centre National de la Recherche Scientifique - UGA [2016-2019] - Université Grenoble Alpes [2016-2019]Jankowski, PiotrPiotrJankowskiStoecklin, ThierryThierryStoecklinUB - Université de BordeauxSzalewicz, KrzysztofKrzysztofSzalewiczOn the importance of full-dimensionality in low-energy molecular scattering calculationsHAL CCSD2016[SDU] Sciences of the Universe [physics]POTHIER, Nathalie2022-06-09 16:50:422023-05-01 03:59:322022-06-09 16:50:43enJournal articleshttps://insu.hal.science/insu-03691535/document10.1038/srep28449application/pdf1Scattering of H<SUB>2</SUB> on CO is of great importance in astrophysics and also is a benchmark system for comparing theory to experiment. We present here a new 6-dimensional potential energy surface for the ground electronic state of H<SUB>2</SUB>-CO with an estimated uncertainty of about 0.6 cm<SUP>-1</SUP> in the global minimum region, several times smaller than achieved earlier. This potential has been used in nearly exact 6-dimensional quantum scattering calculations to compute state-to-state cross-sections measured in low-energy crossed-beam experiments. Excellent agreement between theory and experiment has been achieved in all cases. We also show that the fully 6-dimensional approach is not needed with the current accuracy of experimental data since an equally good agreement with experiment was obtained using only a 4-dimensional treatment, which validates the rigid-rotor approach widely used in scattering calculations. This finding, which disagrees with some literature statements, is important since for larger systems full-dimensional scattering calculations are currently not possible.