Incident azimuth angle

Fig. 5. Ni(7 911) with adsorbed CO. (a) Proposed structure. The open circles represent Ni atoms and the shaded circles are CO molecules. The numbers refer to the incident azimuthal angle of the primary ion. (b) NiCO intensity versus azimuthal angle of the bombarding Ar ion. The nickel surface was exposed to 0.6 L of CO. The solid line represents the experimental data and the dashed line results from the classical dynamical calculation. The additional peak at = 60° is not yet...

Incident azimuth angle (< j) the fixed 180° angle from the XB axis to the projection of the incident direction onto the XB-YB plane. Note It is convenient to use a beam coordinate system (see Fig. A2) in which = 180° because this makes the correct angle to use directly in the familiar form of the grating equation. Conversion to a sample coordinate system is straight forward, provided the sample location and rotation are known ... 

The projection of the incident direction onto the sample face is the —XB axis. Azimuth angles are measured from the XB axis. The incident azimuth angle, is always 180° so used directly in the common form of the grating equation (Fig. A2). 

Figure Bl.23.8. Scattering intensity of 2 keV Ne versus azimuthal angle 6 scans for Pt 110] in the (1 x 2) and (1 X 3) reconstructed phases. Scattering angle 0 = 28° and incident angle a = 6°.

The polarizer and analyzer azimuthal angles relative to the plane of incidence must be calibrated. A procedure for doing this is based on the minimum of signal that is observed when the fast axes of two polarizers are perpendicular to each other. For details the reader can consult the literature."... 

Fig. 3.62. Examples ofTOF-SARS spectra for Kr scattering from CdS -time-of-flight spectrum, scans for the angle of incidence a, and the azimuthal angle S [3.149].

The differential scattering cross section dCsc /dQ, a familiar quantity in atomic physics, is defined as the energy scattered per unit time into a unit solid angle about a direction —which may be specified by two angles, the scattering angle 6 and the azimuthal angle (see Fig. 3.3)—for unit incident irradiance. It is expressed in terms of the scattered irradiance Is(0, ), the incident irradiance /, and the distance r to the detector as... 

Fig. 4.7. Normalized scattered intensity vs. angle from surface normal for an azimuthal angle of 0 = 24° with a fixed angle of incidence of 45° on a stepped Pt(553) surface...

Several studies have appeared which examine the SH response from bulk single crystals of gold under potential control. The first study reported was that of Koos [134] in which both the native and underpotential deposition of thallium was studied. This was later examined in more detail for a series of different metals on Au(lll) [155]. Fig. 5.23 shows the SH intensity from Au(lll) in HC104 as a function of the azimuthal angle 0. The SH response using a 1064 nm incident beam was collected for p-polarized input and p- and s-polarized output (Fig. 5.23 a and c) and s-polarized input and p-polarized output (Fig. 5.23 b). The responses are consistent... 

Figure 3. Dependence of Ni ion yield on azimuthal angle at various pol r angle for clean Ni(001) bombarded by 1500 eV Ar ions at normal incidence. The solid curves represent experimental data while the dashed curves are predicted values obtained by correcting the calculated yields for 1000 eV Ar ion bombardment for the presence of the image force.

Thus, the low temperature adsorption of CO on Ni 7 9 11) presents a realm of interesting structural phases which should be sensitive to the azimuthal angle of incidence of the primary ion beam. 

For the elastic scattering of a beam of unpolarized projectiles by an unpolarized target, the cross section has axial symmetry about the incident beam direction and therefore no dependence upon the azimuthal angle 4>, so that the differential elastic cross section is related to its integral counterpart by... 

In a scattering experiment a beam of electrons of momentum k hits a target. We consider the target to be represented by a potential V(r). Electrons are observed by a detector placed at polar and azimuthal angles 9,(f) measured from the direction of the incident beam, which is the z direction in a system of spherical polar coordinates (fig. 4.2). For a central potential the problem is axially symmetric. Relevant quantities do not depend on (f). The detector subtends a solid angle... 

In a kinematically-complete ionisation experiment for an incident beam of momentum ko, the differential cross section is normally measured for a range of a single variable determining the momenta k/ and k of the faster and slower final-state electrons. The kinematic variables are the kinetic energies /, Eg, the polar angles Of, 6s, measured from ko, and the relative azimuthal angle... 

Fig. 11. Azimuthal dependence of FT-RAIRS spectra for TiO2(110)-Rh(CO)2 [72], The azimuthal angle (j) is defined as 0° when the incident radiation is aligned in a plane parallel to the <110> direction. The Vsym(C-O) dynamic dipole is aligned normal to the surface and couples to Pn (transmission band), and Vasym(C-O) is aligned parallel to the surface in the <110> direction, and couples to Pt (absorption band). Two possible adsorption geometries consistent with the FT-RAIRS azimuthal dependence are shown for the gem-dicarbonyl.

Ti 3p core level, distinct increases in ion current also correlated with increases of the secondary electron emission as shown Fig. 3. As no core levels for O and Ti atoms exists at this energy it can be concluded that the sharp increases are due to an enhancement of the ion yield produced by secondary electrons from the Ti02 sublayer. It was also observed that these thresholds are very sensitive to the azimuth angle of the incident electron at the surface. It would appear that this phenomena could be related with the work of Maschhoff, Pan and Madey on the backscattered diffraction of electrons by the Ti02 sublayer [105]. 

Radiation is emitted by all parts of a plane surface in a)t directions into the hemisphere above llte surface, and the directional distribution of emitted (or incident) radiation is usually not uniform. Therefore, we need a quantity that describes the magnitude of radiation emitted (or incident) in a specified direction in space. This quatuity i.s radialion intensity, denoted by/. Before we can describe a directional quantity, we need to specify direction in space. The direction of radiation passing through a point is best described in spherical coordinates in terms of the zenith angle 6 and the azimuth angle , as shown in... 

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