Angle-of-incidence effect

For off-normal bombardment, the sputtering yield initially increases to a maximum then decreases rapidly as the bombarding particles are reflected from the surface this effect is called the angle-of-incidence effect , as shown in Figure 7.3. The maximum sputtering yield... 

Geometrical shadowing effects (angle-of-incidence effects)... 

Angle-of-incidence effect (film growth) The effect of the angle-of-incidence of the adatoms on the development of a film-morphology. See also Columnar morphology. 

In addition to the effect of albedo on the amount of radiation that reaches the earth s surface, the angle of incidence of the radiation compared to the perpendicular to the surface affects the amount of radiation flux on an area. The flux on a horizontal surface is as follows ... 

In the discussion so far we have considered the typical LEIS experiment only, i.e. large angles of incidence of exit relative to the surface plane. Under these conditions, in general, quantitative composition analysis is possible, because the ion-target interaction can be considered as a binary collision, because of the absence of matrix effects (see below). 

From this equation it can be seen that the depth of penetration depends on the angle of incidence of the infrared radiation, the refractive indices of the ATR element and the sample, and the wavelength of the radiation. As a consequence of lower penetration at higher wavenumber (shorter wavelength), bands are relatively weaker compared to a transmission spectrum, but surface specificity is higher. It has to be kept in mind that the refractive index of a medium may change in the vicinity of an absorption band. This is especially the case for strong bands for which this variation (anomalous dispersion) can distort the band shape and shift the peak maxima, but mathematical models can be applied that correct for this effect, and these are made available as software commands by some instrument manufacturers. 

S-polarised light is effectively blind to adsorbed and near-surface species at all angles of incidence. 

The coefficient of infrared light absorption by an adsorbed molecular monolayer of the surface concentration N/F depends both on the angle of incidence reckoned from a normal to the surface and on the effective absorption cross-section o(ft>) 122... 

However, at grazing incidence angles near the critical angle the reflected beam becomes important, and eventually becomes dominant. This is an important effect and the two-beam case is seriously in error for angles of incidence close to the critical angle. Fortunately, the reflected beam decreases in intensity as the fourth power of the scattering angle, and is weak compared with the diffracted... 

T. Nguyen and E. Byrd, FTIR-RA spectral characteristics of epoxy coatings on cold-rolled steel effects of film thickness and angle of Incidence, Appl. Spectrosc. submit for publication, 1985. 

---