ABSTRACT
Generally speaking, spectroscopic methods of analysis aim to determine the chemical composition of a sample through the interaction of an electromagnetic beam (EMB) with the matter. This beam is characterised by its intensity (I0) and its wavelength (λ0). The different beam-matter interaction modes involved in spectroscopic techniques are schematically described in Figure 1. The incident beam can be: Interaction eMB-matter. A model shows an incident beam represented by a horizontal arrow striking a rectangular object. Three labeled arrows emerge: a transmitted beam continues straight, a diffused beam angles upward, and an emitted beam angles downward. All arrows are labeled to indicate their respective paths after interaction. https://www.w3.org/1999/xlink" xlink:href="https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003709992/4a74ae9c-485a-4c2b-9829-71d4291515ea/content/annot_page54_1.tif"/>
absorbed by the matter at the atomic, molecular or at a higher level, and the analysed beam is the transmitted one, which characterised by (I < I0, λ0),
1. absorbed by the matter and lead to emission of electrons (photoelectric effect) or photons (fluorescence or phosphorescence phenomena with λ < λ0),
diffused by diffraction in ordered matter leading to constructive and destructive interferences, in this case the analysis focuses on the angle of diffraction,
diffused by reflection, the resulting beam having same λ0 but lower intensity (I’ < I0).
