excitationsspektra

Exzitationsspektra, also called excitation spectra, are measurements in which the response of a sample is recorded as a function of the energy (or wavelength) of the excitation used to promote it to higher energy states. Peaks in an excitation spectrum indicate energies at which excitation pathways are most effective, revealing information about electronic, vibrational, or magnetic transitions. They are distinct from emission or absorption spectra, which monitor emitted or absorbed photons rather than the efficiency of excitation.

Experimentally, excitation spectra can be obtained in several ways. In fluorescence spectroscopy, one records the emission intensity at a fixed wavelength while varying the excitation wavelength; the resulting curve is the fluorescence excitation spectrum. In absorption spectroscopy, scanning the incident energy yields an absorption spectrum, which can be related to excitation processes. Other techniques that yield excitation spectra include resonant inelastic scattering, electron energy loss spectroscopy, and inelastic neutron scattering, each probing different types of excitations such as electronic, vibrational, or magnetic modes.

Interpretation of an excitation spectrum focuses on the positions and shapes of its features. Peak positions identify the energies of allowed transitions to excited states. Peak intensities reflect transition probabilities and state lifetimes, while broadening provides information about vibronic coupling, disorder, temperature, or interactions with the environment. In solids, spectra may feature excitons or phonons, and in molecules they reflect electronic and vibronic structure.

Applications of excitationsspektra span atoms, molecules, semiconductors, nanomaterials, and luminescent materials. They are used to characterize electronic structure, energy transfer pathways, defect or dopant levels, and the effect of external conditions such as temperature, pressure, or chemical environment on excited states.