Hydrogen dissociation on

Butler D A and Hayden B E 1995 The indirect channel to hydrogen dissociation on W(100)c(2 2)Cu—evidence for a dynamical precursor Chem. Phys. Lett. 232 542... 

An alternative approach is the interpolation of the ab initio PES by some suitable analytical or numerical scheme. For the six-dimensional quantum dynamical studies of hydrogen dissociation on Pd(l 0 0) and Cu(l 0 0) discussed in the next section, ab initio potential energy surfaces have been fitted to an analytical representations [5, 10, 13, 15, 38]. 

In contrast to H2/Pd, the vibrational effects in the adsorption of H2/Cu(l 0 0) are mainly caused by the curved reaction path. The basic mechanism can be discussed within a two-dimensional elbow plot shown in Fig. 2b. The PES corresponds to a so-called late barrier system which refers to the fact that the barrier is located after the curved region of PES. If the molecule is already initially vibrating, i.e. if it is oscillating back and forth in the d-direction, then the vibrational energy can be very efficiently used to make it around the curve and enter the dissociation channel. Nevertheless, adiabatic effects as just discussed in the context of the hydrogen dissociation on Pd(l 00) also contribute to the vibrational effects for H2/Cu(l 0 0). 

Figure 1 Hydrogen dissociation on Cu(l 1 0) [12]. The initial dissociative sticking probability Sq is measured as a function of incident translational energy E. Measurements are made by increasing die nozzle temperature Ta ( ), and by seeding at constant nozzle temperature (Tn = 1100 K) ( ). The latter measurement provides a measure of die translational energy onset (ca. 125 meV)...

Hydrogen dissociation on tungsten is facile, with significant probabilities of dissociation at very low... 

Fig. 1.56. In the example depicted in this figure, a bifunctional catalyst like platinum on silicon oxide enables the isomerization of methyl-cyclopropane to buten-2 as well as its hydrogenation to butane [349]. The isomerization proceeds on the oxide support. Hydrogen dissociates on the metal particle and the H-atoms spillover onto the oxide support material where they are mobile to react with butene...

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