Adsorption and desorption of CO on Ru(0001): A comprehensive analysis

Role of Vibrational Excitation of the Adlayer in 'Precursor-Mediated' Sticking Probabilities of CO on Metal Surfaces: A Kinetic Model

“…Particles in the precursor state are mobile across the surface and one classifies precursors into intrinsic when the particle is trapped at an empty lattice site and extrinsic when trapped above an occupied site. A kinetic lattice gas model has recently been employed [21] for computing the dependence of S on surface coverage and temperature in the presence of precursors and lateral interactions and applied to CO adsorption on Pt(111) [22] and Ru(0001) [23]. Figure 1, reproduced from [23], shows the theoretical behavior of S dir (topsites + bridge-sites) on Pt(111) in the case of direct sticking and in the presence of lateral repulsion, which implies site exclusion during adsorption.…”

“…A kinetic lattice gas model has recently been employed [21] for computing the dependence of S on surface coverage and temperature in the presence of precursors and lateral interactions and applied to CO adsorption on Pt(111) [22] and Ru(0001) [23]. Figure 1, reproduced from [23], shows the theoretical behavior of S dir (topsites + bridge-sites) on Pt(111) in the case of direct sticking and in the presence of lateral repulsion, which implies site exclusion during adsorption. In addition, the computation of the sticking coefficient, S prec , has also been performed in [23] in the case of negligible desorption rate from the chemisorbed state.…”

“…Figure 1, reproduced from [23], shows the theoretical behavior of S dir (topsites + bridge-sites) on Pt(111) in the case of direct sticking and in the presence of lateral repulsion, which implies site exclusion during adsorption. In addition, the computation of the sticking coefficient, S prec , has also been performed in [23] in the case of negligible desorption rate from the chemisorbed state. In particular, S dir and S prec are related through the equation [22] …”

“…5.2 (solid diamonds). "True" sticking probabilities S as determined in [17] from the observed total adsorption rate J/F (full circles) and in [23] from theoretical calculations (dashed red line). Thin lines are guides for the eyes.…”

“…[8] at T = 390 K according to the method described above and theoretical values of S from Ref. [23] (S [23]). Adsorption-stimulated desorption is thus apparently important at T = 394 K and is still present at T = 334 K [12,17] so that the sticking probability measurements of Ref.…”