O-atom exchange in O(3P)Â +Â H2O(1A1) collisions

► O(3P) + H2O(1A1) global potentials are used to explore two new reaction paths. ► Both cross a D2h rhombus point, with zero gradient and two imaginary frequencies. ► One frequency motion leads to O + H2O, while the second motion leads to OH + OH. ► In each case, an O-atom is exchanged. ► Cross sections and rate constants are computed for these processes.