Nitrogen recombination on Pd

Ohno et al. [79] measured the angle resolved translational energy distributions for N2 formed during NO and N20 thermal desorption (Fig. 24). They found that both NO and N20 TPR gave very similar 

The N2 rotational distribution also showed a sub-thermal distribution (Fig. 27) with a rotational temperature of 450 K, similar to the translational temperature. Despite the cold translational and rotational distributions, the vibrational co-ordinate is excited, with excess population in the high vibrational states. Remarkably, this result had been suggested previously on the basis of threshold ionisation measurements of N2 desorbed from Pd covered field ionisation tips [129]. Unlike the translational energy distributions observed for desorption from Ru(0001) [103], the energy release on Pd(l 1 0) does depend on the vibrational state, (E) decreasing rapidly for excited N2(u) states [127]. A cold translational distribution is indicative of desorption from a bound state, where cooling of the adsorbate hindered 

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