title: Unraveling the hydration-induced ground-state change of AtO+by relativistic and multiconfigurational wave-function-based methods.
abstract: The AtO+cation is one of the main chemical forms that appear in the astatine Pourbaix diagram. This form can react with closed-shell species in solution, while in the gas phase, it has a spin-triplet ground spin-orbit-free (SOF) state. Spin-orbit coupling (SOC) mixes its MS= 0 component with the1Σ+singlet-spin component, while keeping an essentially-spin-triplet SOC ground-state. Therefore, it was suggested that AtO+undergoes a hydration-induced ground-state change to explain its reactivity in solution with closed-shell species [J. Phys. Chem. B, 2013, 117, 5206-5211]. In this work, we track the nature of the low-lying SOF and SOC states when the hydration sphere of AtO+is stepwise increased, using relativistic and multiconfigurational wave-function-based methods. This work clarifies previous studies by (i) giving additional arguments justifying a solvation-induced ground-state change in this system and (ii) clearly identifying for the first time the nature of the involved SOF and SOC many-electron states. Indeed, we find at the SOF level that AtO+undergoes a ground-state reversal between3Σ-and the closed-shell component of1Δ, which leads to an essentially-spin-singlet and closed-shell SOC ground-state. This explains the observed reactivity of AtO+with closed-shell species in solution.
authors.affiliation: SUBATECH, UMR CNRS 6457, IN2P3/EMN Nantes/Université de Nantes, 4 Rue A. Kastler, BP 20722, 44307 Nantes Cedex 3, France. remi.maurice@subatech.in2p3.fr and CEISAM, UMR CNRS 6230, Université de Nantes, 44322 Nantes Cedex 3, France. nicolas.galland@univ-nantes.fr.
authors.forename: Dumitru-Claudiu
authors.initials: DC
authors.lastname: Sergentu
authors.affiliation: PhLAM, UMR CNRS 8523, Université de Lille 1, 59655 Villeneuve d'Ascq Cedex, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Réal
authors.affiliation: SUBATECH, UMR CNRS 6457, IN2P3/EMN Nantes/Université de Nantes, 4 Rue A. Kastler, BP 20722, 44307 Nantes Cedex 3, France. remi.maurice@subatech.in2p3.fr.
authors.forename: Gilles
authors.initials: G
authors.lastname: Montavon
authors.affiliation: CEISAM, UMR CNRS 6230, Université de Nantes, 44322 Nantes Cedex 3, France. nicolas.galland@univ-nantes.fr.
authors.forename: Nicolas
authors.identifier: http://orcid.org/0000-0001-5618-226X
authors.initials: N
authors.lastname: Galland
authors.affiliation: SUBATECH, UMR CNRS 6457, IN2P3/EMN Nantes/Université de Nantes, 4 Rue A. Kastler, BP 20722, 44307 Nantes Cedex 3, France. remi.maurice@subatech.in2p3.fr.
authors.forename: Rémi
authors.initials: R
authors.lastname: Maurice