Isotope Effect in D2O Negative Ion Formation in Electron Transfer Experiments: DO-D Bond Dissociation Energy

Authors: Kumar, Sarvesh; Hoshino, Masamitsu; Kerkeni, Boutheina; Garcia, Gustavo; Limao-Vieira, Paulo

Journal: JOURNAL OF PHYSICAL CHEMISTRY LETTERS

Publication date: 2023/06/05

DOI: 10.1021/acs.jpclett.3c00786

Abstract: H2O/D2O negative ion time-of-flightmassspectra from electron transfer processes at different collision energieswith neutral potassium yield OH-/OD-, O-, and H-/D-. The branching ratios show a relevant energy dependence with animportant isotope effect in D2O. Electronic state spectroscopyof water has been further investigated by recording potassium cationenergy loss spectra in the forward scattering direction at an impactenergy of 205 eV (lab frame), with quantum chemical calculations forthe lowest-lying unoccupied molecular orbitals in the presence ofa potassium atom supporting most of the experimental findings. TheDO-D bond dissociation energy has been determined for the firsttime to be 5.41 +/- 0.10 eV. The collision dynamics revealed thecharacter of the singly excited (1b(2) (-1)) molecular orbital and doubly excited states in such K-H2O and K-D2O collisions.