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Energetic particles, interactions with surface

R. E. Johnson, Energetic Charge-Particle Interaction with Atmosphere Surface (Springer-Verlag, Berlin, 1990). [Pg.415]

An energetic particle hitting a surface or interacting with a gas may... [Pg.4]

The dynamics of ion surface scattering at energies exceeding several hundred electronvolts can be described by a series of binary collision approximations (BCAs) in which only the interaction of one energetic particle with a solid atom is considered at a time [25]. This model is reasonable because the interaction time for the collision is short compared witii the period of phonon frequencies in solids, and the interaction distance is shorter tlian the interatomic distances in solids. The BCA simplifies the many-body interactions between a projectile and solid atoms to a series of two-body collisions of the projectile and individual solid atoms. This can be described with results from the well known two-body central force problem [26]. [Pg.1801]

Previous studies of the interaction of energetic particles with suri ces have made it clear that under nearly all conditions the majority of atoms or molecules removed from a surface are neutral, rather than charged. This means that the chained component can have large relative fluctuations (orders of magnitude) depending on the local chemical matrix. Calibration with standards for surfaces is difficult and for interfaces is nearly impossible. Therefore, for quantification ease, the majority neutral component of the departing flux must be sampled, and this requires some type of ionization above the sample, often referred to as post-ionization. SALI uses effi-... [Pg.561]

The theory of equilibrium adsorption and kinetics of adsorption upon the surface of adsorbents have been thoroughly treated in the Russian literature since experimental results were obtained which did not agree with Langmuir s initial assumptions (1) that the surface of the adsorbent is energetically uniform (2) that the adsorbed particles do not interact with one another (3) that the surface is covered by only a monolayer of the adsorbate. If the third assumption is retained then three alternative possibilities are offered (a) assumption (1) is rejected and assumption (2)... [Pg.238]

Figure 25.5 Variation of the potential energy of an adsorbed H atom parallel to the surface, E(x,y). Three different cases are shown (a) single particle adsorption with no lateral interactions equivalence of all adsorption sites (b) repulsive interactions, co, between neighboring adsorbed H atoms with the consequence of energetically inhomogeneous adsorption sites (c) attractive interactions, co, between neighboring H atoms leading to energetically more favorable adsorption sites in the direct vicinity of an already adsorbed H atoms. Figure 25.5 Variation of the potential energy of an adsorbed H atom parallel to the surface, E(x,y). Three different cases are shown (a) single particle adsorption with no lateral interactions equivalence of all adsorption sites (b) repulsive interactions, co, between neighboring adsorbed H atoms with the consequence of energetically inhomogeneous adsorption sites (c) attractive interactions, co, between neighboring H atoms leading to energetically more favorable adsorption sites in the direct vicinity of an already adsorbed H atoms.

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See also in sourсe #XX -- [ Pg.81 ]




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