Normal kinetic energies

Figure 3.29. CH4 dissociation probability SQ (or S in this chapter) on Ni(100) plotted logarithmically vs. the normal kinetic energy En. (a) as a function of vibrational temperature Tv as noted in the figure. The lines are the fits of eq. (3.2) to the experiments. From Refs. [267,268]. (b) is for vibrationally state-resolved dissociation measurements, with CH4 in the Vj (solid triangles facing upwards), 2v3(open squares), v3 (open downward facing traingles) and v = 0 (solid circles) vibrational states. From Ref. [117].

Figure 3.32. H2 Sticking (dissociative adsorption) probability S on Pd(100) as a function of incident normal kinetic energy Et = En. Circles are experiment [304], dashed and solid line are 6D first principles quantum dynamics with H2 in the ground state and a thermal distribution appropriate to the experiments, respectively [109]. The inset is also 6D first principles quantum dynamics but based on a better PES [309]. From Ref. [2].

From the gaseous films it is learned that the molecules have the normal kinetic energy of translatory motion in the two dimensions, of the surface, kT, per degree of freedom. 

Figure 4. Initial sticking coefllcient for various incident angles, as labeled on the figure for the H2/Ni(100) system (a) as a function of the initial kinetic energy (Rendulic et al. 1989) (b) as a function of the initial normal kinetic energy (Hamza and Madix 1985). Ignore the specification of n on a.

Figure 7. Initial sticking coefTicient as a function of the initial normal kinetic energy for ...

Figure 15. Rotational distributions of scattered NO from Ag(l 11) at different initial normal kinetic energies, from Kleyn et al. (1982) with permission.

Figure 28. Vibrational excitation probability for the NO/Ag(IIl) system as a function of the initial normal kinetic energy. The curve is from Newns (1986) while the experimental data points are from Rettner et al. (1985b)...

Figure 35, (a) Variation of the initial sticking coeiiicient with initial normal kinetic energy (circles represent experimental results from Hamza and Madix (1985) while triangles and squares represent classical GLE calculations at incident angles of 0° and 45°, respectively) (b) calculated number density of scattered Hj vs. final polar angle (c) calculated initial rotational state dependence of the dissociation probability. The plots are from Kara and DePristo (1989). 

Ions in the coUision cell experience a statistically distributed number of collisions, and thus acquire a range of velocities on exiting the chamber. This results in wider than normal kinetic energy distributions in the second TOP, and thus a greatly reduced resolution of the fragment ion signals. 

Theory of the Motion.— The theory of Einstemf (v. Smoluchowski came independently to the same result) assumes no difference between true molecules and particles suspended in the same medium. The particles behave as if they were true gas molecules with normal kinetic energy but a much shorter free path. The following is the Einstein formula. 

An ion beam mainly comprises normal ions, all having the same kinetic energy gained on acceleration from the ion source, but there are also some ions in the beam with much less than the full kinetic energy these are called metastable ions. 

Eigure 20 compares the predictions of the k-Q, RSM, and ASM models and experimental data for the growth of the layer width 5 and the variation of the maximum turbulent kinetic energy k and turbulent shear stress normalized with respect to the friction velocity jp for a curved mixing layer... 

The Cannon-Fenske viscometer (Fig. 24b) is excellent for general use. A long capillary and small upper reservoir result in a small kinetic energy correction the large diameter of the lower reservoir minimises head errors. Because the upper and lower bulbs He on the same vertical axis, variations in the head are minimal even if the viscometer is used in positions that are not perfecdy vertical. A reverse-flow Cannon-Fen ske viscometer is used for opaque hquids. In this type of viscometer the Hquid flows upward past the timing marks, rather than downward as in the normal direct-flow instmment. Thus the position of the meniscus is not obscured by the film of Hquid on the glass wall. 

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