Scans and Resolution in Angular and Reciprocal Space

Abstract

In this and in the next chapters we show that the scattered intensity can be expressed as a function of the scattering vector

$$ Q = K - {K_i},$$

(3.1)

if the the direction of the perfectly monochromatic incident plane wave is described by its wave vector K _i and that of scattered wave by K. Therefore, the angular distribution of the scattered intensity, representing the properties of the sample, can be described by its distribution in reciprocal space (reciprocal-space map). Strictly speaking, this expression is applicable only if the wave vectors K and K _i and the surface normal vector n lie in the same plane (scattering plane). This scattering geometry is called coplanar. As we show later, in the non-coplanar scattering geometry (in particular, in the grazing-incidence diffraction — GID, see Sect. 4.3) the scattered intensity depends on both vectors K _i and K independently.