We employ time-slice and velocity map ion imaging methods
to explore
the quantum-state resolved dynamics in thermal N2O decomposition
on Pd(110). We observe two reaction channels: a thermal channel that
is ascribed to N2products initially trapped at surface
defects and a hyperthermal channel involving a direct release of N2to the gas phase from N2O adsorbed on bridge sites
oriented along the [001] azimuth. The hyperthermal N2is
highly rotationally excited up toJ= 52 (v″ = 0) with a large average translational energy
of 0.62 eV. Between 35 and 79% of the estimated barrier energy (1.5
eV) released upon dissociation of the transition state (TS) is taken
up by the desorbed hyperthermal N2. The observed attributes
of the hyperthermal channel are interpreted by post-transition-state
classical trajectories on a density functional theory-based high-dimensional
potential energy surface. The energy disposal pattern is rationalized
by the sudden vector projection model, which attributes to unique
features of the TS. Applying detailed balance, we predict that in
the reverse Eley–Rideal reaction, both N2translational
and rotational excitation promote N2O formation.