What is spectroscopy and what it means


Spectroscopy, Spectrometry, Branch of science that studies the interaction between electromagnetic radiation and material media, whereby a spectral decomposition of the electromagnetic radiation (analysis of the frequencies and intensities contained) is carried out. The intensity of electromagnetic radiation plotted as a function of frequency, wavelength or wave number is called the spectrum. Devices for spectroscopic examinations are called spectral apparatus.

The S. can be divided according to very different points of view: 1) According to the Type of observation of the spectrum. The examined sample can absorb electromagnetic radiation (absorption spectroscopy) or emit (emission spectroscopy, spectrum). In addition, the spectral investigation of reflected light (reflection spectroscopy) and scattered light (Raman spectroscopy) also plays a role. 2) After the Type of sample examined. Depending on whether there is an interaction of electromagnetic radiation with atoms, molecules or solids, one speaks of atomic spectroscopy, molecular spectroscopy or solid-state spectroscopy. 3) According to the ones used for the investigation differentAreas of the electromagnetic spectrum. A distinction can be made between: X-ray spectroscopy, gamma ray spectroscopy, UV-VIS spectroscopy, infrared spectroscopy, microwave spectroscopy, high-frequency spectroscopy. 4) After the Type of interaction. A distinction is made between electron spectroscopy, vibration spectroscopy, rotation spectroscopy, electron spin resonance spectroscopy, NMR spectroscopy, and nuclear quadrupole resonance spectroscopy. 5) Certain types of spectroscopy will be after yourExplorer and / or named founder, e.g. B. Raman spectroscopy, Fourier spectroscopy.

The S. in the broader sense also includes examination methods which, as a result of the absorption of electromagnetic radiation, lead to particle emission (Mössbauer spectroscopy, photoelectron spectroscopy, Auger electron spectroscopy) or to the formation of ions (mass spectrometry) or secondary electrons after being bombarded with particles.

The special significance of S. for chemistry lies in the fact that one does not investigate electromagnetic radiation per se, but rather that which has previously interacted with a material medium. The appearance of discrete frequencies in the spectrum after this interaction indicates that these are directly linked to the material properties determined by quantum conditions. The relationship Δ appliesE. = E.2E.1 = Ha·ν, where E.1, E.2are quantized energy states of the substance under investigation, the energy difference of which is ΔE. in the form of electromagnetic radiation of frequency v occurs. H is Planck's quantum of action. It is therefore understandable that with the help of the S. essential knowledge about the atomic structure and the structure of molecules and solids could be obtained. In the wide range of electromagnetic radiation, the quantized energy levels correspond to very different physical states, such as B. electron levels, vibration levels, electron spin or nuclear spin states. Depending on the spectral range, the S. is therefore able to provide information about the most varied of properties of the measured samples, whereby the observed frequencies are directly related to their structure and allow statements to be made about the structural structure or the qualitative composition of the systems examined. Statements about the quantitative composition of the sample can be obtained from the intensities.