The atomic and molecular spectroscopy is a powerful tool
to analyse chemical composition or structure of a sub-stance, which may be a pure compound or a simply mixture or solution of two or more different phases of a crys-talline or amorphous material. The chemistry and indust-
ry people sometimes also talk of minerals, ores, and
pollutants, but these comprise the same crystalline or amorphous structures. They are characterized using the same instrumental techniques
