Spectroskopia

Spectroskopia (spectroscopy) is the study of the interaction between matter and electromagnetic radiation, typically involving measurement of light intensity as a function of wavelength, frequency, or energy. Techniques observe absorption, emission, or scattering of light and use the resulting spectra to infer the composition, structure, and properties of materials.

Common methods include ultraviolet-visible (UV–Vis) absorption spectroscopy, infrared (IR) spectroscopy, Raman spectroscopy, fluorescence spectroscopy, and atomic emission spectroscopy. UV–Vis probes electronic transitions; IR and Raman reveal vibrational modes and molecular structure; fluorescence detects emitted light from excited states; atomic emission analyzes elemental composition after excitation in flames, plasmas, or other sources.

Principles rely on quantized energy levels. Photons promote or de-excite electrons or vibrational modes, producing characteristic spectral features. In absorption spectroscopy, Beer–Lambert law relates absorbance to concentration via A = εlc. Emission techniques yield spectral lines associated with specific elements or compounds.

Instrumentation typically comprises a light source, a sample compartment, a dispersive element or interferometer to resolve wavelengths, and a detector (such as a photodiode, PMT, or CCD). Data processing includes calibration, baseline correction, and comparison with reference spectra.

Applications span chemistry, physics, astronomy, environmental science, medicine, forensics, and materials science. Spectroskopia enables qualitative identification and quantitative analysis, often non-destructive and rapid. Limitations include spectral overlap, matrix effects, need for calibration, and limited resolution or sensitivity for certain samples, which require careful experimental design and data interpretation.