Fig. 3: Scattering of O(1D) from HOPG leads to a spin non-conserving O(1D) → O(3P) channel that exhibits electronic-to-kinetic energy transfer.
From: Spin-dependent reactivity and spin-flipping dynamics in oxygen atom scattering from graphite
a, The flux of incident O(3P2) (blue stars), incident O(1D) (black squares) and scattered O(3P2) (red circles) in the CO2 photolysis experiment, plotted as a function of tprobe, the time between the photolysis laser and probe laser. b, The tarrive distribution for incident O(1D) and O(3P2) is compared with the tdepart distribution for scattered O(3P2). The widths of the red shaded rectangles indicate the size of the tdepart histogram intervals and the horizontal error bars indicate the FWHM uncertainty in tdepart due to uncertainty in the velocity measurements. The peak at 85 μs (marked with an asterisk) is an artefact due to a small contamination of O2 in the CO2 molecular beam. A comparison of the profile of the tdepart distribution with the tarrive distributions indicates that incident O(1D) atoms are converted to O(3P) during the scattering process. c, The scattering kinetic energy distribution for the O(1D) → O(3P2) channel is shown for incident O assigned to Ei = 0.065 ± 0.020 eV (blue stars). The distribution of incidence energies (including experimental uncertainty) is shown as a blue dashed curve. Atoms gain kinetic energy during the scattering process due to electronic-to-kinetic energy coupling. d, The scattered O(1D) → O(3P2) kinetic energy distribution from the CO2 photolysis source assigned to Ei = 0.23 ± 0.02 eV (black squares) is compared to the distribution obtained from the O2 discharge source (red circles) with a similar range of incidence energies (Ei = 0.23 ± 0.05 eV), indicating that, on average, incident O(1D) atoms scatter with higher kinetic energy than incident O(3P) atoms with similar incidence kinetic energy. The incidence energy distributions are indicated by black and red dashed curves, respectively.
