Stereodynamics in Dissociative Adsorption of NO on Si(111)

Abstract

We report results of our study on the surface-temperature dependence of the steric effect in the dissociative adsorption of NO on Si(111)-(7x7). Data presented here show that, at an incident energy of 58 meV, the reactive sticking probability for the N-end collision is larger than that for the O-end collision. Furthermore, this steric preference is quite sensitive to the surface temperature and the surface coverage. This study shows that the transient surface trapping into a shallow precursor well plays a key role in the stereodynamics of the dissociative adsorption at the low energy region.

Dynamical steering in an electron transfer surface reaction: Oriented NO(v = 3, 0.08 < Ei < 0.89 eV) relaxation in collisions with a Au(111) surface

“…In a first step, the IR laser excites either the low or high field seeking state in v = 3 via the Q 11 (0.5) e or Q 11 (0.5) f line, respectively. After scattering from the Au(111) surface, populations of NO molecules in v = 3, v = 2, or v = 1 are probed via the A 2 + (v = 0)←X 2 (v = 3,2,1) bands, respectively. The dotted arrows illustrate the two different approaches described in the text.…”

“…[1][2][3][4][5][6] Experiments with adsorbed molecules also reveal strong orientational influences, for example, surface aligned photochemistry. [7][8][9] This raises an important question: When oriented molecules approach a surface adsorption site, to what extent does the growing interaction with the surface re-orient the molecule either away from or towards a favorable reactive geometry?…”

Supersonic Molecular Beam Experiments on Surface Chemical Reactions

“…Steric asymmetry parameter R as a function of ΘTotal at Ts = 330 K (triangles), 400 K (circles) and 600 K (squares). [103] The ΘTotal for exposure of randomly oriented NO is used for the plot of R. The possible interaction potential of NO/Si (111) (511) by HOMB, even at ∼300 K. These HOMB-induced oxide-formation processes are important for fabricating copper oxide at and below RT, which is quite important for device technology. Moreover, HOMB also has great potential for fabricating various metastable phases for the synthesis of new nanostructured materials.…”

“…Thus, we perform the direct observation of the surface products created by the oriented NO beam. [91,102,103] Figure 14 shows the orientation dependence of the O-1s and N-1s XPS spectra, measured at ΘTotal ≈ 0.28 ML for the 58 meV oriented NO |0.5 0.5 0.5〉 beam at Ts = 400 K. It is clear that an N-end collision is more reactive than an O-end collision. Figure 15 shows the total coverage ΘTotal dependence of the stereo-asymmetric factor R. Here, we define R as follows where Si(t), with i = N or O, is the reactive sticking probability for the N-or O-end collision, respectively.…”

A new perspective: imaging the stereochemistry of molecular collisions

“…91,92 However, the effect of molecular orientation on such collisions is beyond the scope of the current Perspective article, and will not discussed further here. A similar expression holds for reactions involving side-on versus end-on molecular alignment of reactants.…”