Incident kinetic energy

J Rettner C T and Mullins C B 1991 Dynamics of the chemisorption of O2 on Pt(111) Dissociation via direct population of a molecularly chemisorbed precursor at high incidence kinetic energy J. Chem. Phys. 94 1626... 

Despite the orientational dependence of the sticking probability, at low incident kinetic energies all molecules are reoriented into favorable binding orientations during the collision. However, they might not actually stick. 

Figure 17.9 Product of the range of an energetic electron in a solid material with the density as a function of the incident kinetic energy is shown. (From Knoll, 2000.)...

Figure 7. Total quenching cross section as function of incident kinetic energy from different experiments and theoretical predictions.

Figure 6 Dissociative adsorption probability of H2 on Cu(l 00) as a function of the incident kinetic energy determined by six-dimensional quantum wave-packet calculations for molecules initially in the vibrational ground state and first excited state, respectively [32], For the vibrational ground state, the calculations are compared to experimental results derived from an analysis of adsorption and desorption experiments [27].

In order to quantify the energy transfer to the e-h pairs, the energy distribution for directly scattered molecules was determined (Fig. 14b). Less than 10% of the incident kinetic energy is transfered to... 

Figure 16 Incidence kinetic energy dependence of the excitation and de-excitation probability for NO(v = 2) scattering from Au(l 1 1) for two surface temperatures. De-excitation (v = 2 -> 1) triangles and diamonds. Excitation (v = 2 -> 3) squares and circles. Lines are explained in the original reference. From Huang et al. [135].

Figure 5 Data adapted from Rettner et al. [10]. Initial sticking probability, S0, vs. incident kinetic energy, E for N2 on W(1 00) at 0 = 0°, and surface temperatures of Ts = 300, 800, and 1000 K.

Figure 6 Data adapted from Hamza et al. [32], Plot of S0 vs. incident kinetic energy, E, for propane on the Ir(l 1 0)—(1 x 2) surface at various surface temperatures, Ts.

Figure 14 shows the initial chemisorption probability, Sa, of methane on Ir(l 1 0) at four different surface temperatures, Ts, as a function of incident kinetic energy. Also shown, is a plot of the trapping probability, a, measured at a surface temperature of Ts = 65 K. Figure 15 shows S as a function of incident kinetic energy for various incident angles, 0j, at a surface temperature of Ts = 1000 K. 

Figure 15 Initial chemisorption probability, S0, vs. incident kinetic energy for methane on Ir(l 1 0)-(l x 2) at Ts = 1000K for incident angles of 0 = 0, 30, 45, and 60°. Nozzle temperature was kept at room temperature (Tn 300 K) for these experiments. Uncertainties in S0 values are 20%. Data adapted from Seets et al. [18].

Schottler and Toennies [152] have employed a velocity-selected Li+ beam to study inelastic collisions giving rise to vibrational excitation in H2. Although individual vibrational levels were not completely resolved in these experiments, it was demonstrated that as the incident kinetic energy of the ions was... 

The data demonstrate the existence of a collisional process that leads to ejection of CO2 (and CO) from an oxidized polymer surface upon impingement of hyperthermal inert atoms or molecules and show that the rate of release of these carbon oxide molecules from the surface rises dramatically with incident kinetic energy above 800 kJ mol. The fact... 

Although deformation of the molecule plays the essential role in how the molecule overcomes the barrier to dissociation, it is not the complete picture of the dissociation mechanism. The remainder of the picture comes into view upon examination of the dissociation probabilities versus translational energy measured for CD4. These measurements are also shown in Fig. 2. The error bars on the CD4 data represent 95% confidence limits of three measurements. The beam of CD4 is normal to the crystal in these measurements and the temperature of the surface is 475 K. As can be seen 1n Fig. 2, the dissociation probability for CD4 is below the detection limit of carbon for incident kinetic energies less than 14 kcal/mole. Above 14 kcal/mole, the dissociation probability of CD4 increases exponentially. However, the dissociation probability of CD4 is always at least a factor of 8 below that of CH4. 

Since increasing the incident kinetic energy, Ej, of the molecule decreases a, Sq will decrease w th increasing kinetic energy in a precursor mechanism. This is one signature of a precursor mechanism often looked for experimentally. ... 

We limit the presentation of experimental data to those experiments utilizing supersonic molecular beam expansions in combination with UHV techniques. Supersonic beam experiments control the incident kinetic energy and angle of the molecule to a high degree, and thus are generally easier to interpret at the microscopic dynamical level than those experiments utilizing effusive beams. 

Figure 14. Mean translational energy, for scattered NO from Ag(l 11) as a function of finai rotational energy for various incident kinetic energies and angies, from Rettner (1988) with permission.

Rettner C T, DeLouise L A and Auerbach D J 1986 Effect of incidence kinetic energy and surface coverage on the dissociative chemisorption of oxygen on W(110) J. Chem. Phys. 85 1131... 

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