Imaging Dynamics on the F + H 2 O → HF + OH Potential Energy Surfaces from Wells to Barriers

Abstract

The study of gas-phase reaction dynamics has advanced to a point where four-atom reactions are the proving ground for detailed comparisons between experiment and theory. Here, a combined experimental and theoretical study of the dissociation dynamics of the tetra-atomic FH 2 O system is presented, providing snapshots of the F + H 2 O → HF + OH reaction. Photoelectron-photofragment coincidence measurements of the dissociative photodetachment (DPD) of the F ¯ (H 2 O) anion revealed various dissociation pathways along different electronic states. A distinct photoelectron spectrum of stable FH–OH complexes was also measured and attributed to long-lived Feshbach resonances. Comparison to full-dimensional quantum calculations confirms the sensitivity of the DPD measurements to the subtle dynamics on the low-lying FH 2 O potential energy surfaces over a wide range of nuclear configurations and energies.