Schematic diagram of the 3D dynamic model used to describe hot electron induced associative desorption of from Ru(0001). All symbols are described in the text.
Diagram of the surface unit cell in the DFT calculations. The large circles are for Ru atoms and the smaller solid circles are H atoms in the configuration. The heavy (blue) circles are surface Ru atoms and the lighter (red) circles are second layer Ru atoms. The small open circle represents H atoms at a distance appropriate to the desorbed molecule. The solid arrows give the assumed desorption path projected onto the surface. The dashed arrows give the higher barrier desorption path.
(a) DFT potential energy (in eV) projected along the minimum energy path for desorption (in angstrom). corresponds to the adsorbed state and corresponds to the asymptote. (b) Electronic friction coefficients along the minimum energy path for desorption .
Contour plot of the two dimensional DFT potential energy surface for for desorption of a single from . Contours are at intervals. The arrow indicates the location of the barrier to associative desorption.
Electronic friction coefficients and as a function of electronic temperature for a point on the desorption path, .
Desorption yield for and as a function of adsorbed laser fluence calculated by the 3D dynamic model. The lines are fits of the power law dependences used to describe the experimental data.
The two pulse correlation for associative desorption at a total adsorbed laser fluence of calculated by the dynamic model. The points are the desorption yield for different delays between the two nearly equal laser pulses. The line through the points is simply a visual aid.
The translational temperature of desorbed and calculated by the dynamic model as a function adsorbed laser fluence .
(a) Typical associative desorption trajectory for following an adsorbed laser fluence of overlayed on the 2D PES. (b) Typical trajectory that does not associatively desorb following an adsorbed laser fluence of overlayed on the 2D PES. (c) The total energy projected onto as a function of time for the two trajectories in (a) and (b) as labeled in the figure. Note the constant with at the time of desorption for the trajectory in (a).
The electron temperature , phonon temperature and adsorbate temperature as a function of time following a laser pulse at of fluence . The bar graph is the induced rate of associative desorption as a function of .
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