Erregungs

Erregung is a term used in various scientific fields to describe the process by which a system gains energy or is brought into a higher-energy state, and the subsequent state itself. In physics and engineering, excitation refers to externally supplied energy that drives motion or maintains a driven response, such as a mechanical system excited by a periodic force or an electrical circuit driven by a pump signal. The amount of energy added is called the excitation energy, and the system may return to its ground state through dissipation, emitting energy as heat or radiation.

In quantum chemistry and atomic physics, electronic excitation denotes a transition of electrons from a lower to a higher energy level within an atom or molecule. Excited states are typically short-lived; relaxation can occur radiatively, releasing photons (fluorescence or phosphorescence), or nonradiatively via vibrational energy transfers. The energy gap between states determines the wavelength of emitted or absorbed light.

In chemistry and photobiology, excitation can refer to molecules absorbing photons to reach reactive states, enabling photochemical reactions and photosynthesis.

In neuroscience, neuronal excitation occurs when membranes depolarize toward threshold, triggering action potentials. Synaptic inputs produce excitatory postsynaptic potentials that raise the likelihood of firing, contrasted with inhibitory inputs that suppress activity.

In spectroscopy and materials science, the study of excitation spectra reveals how materials absorb energy at different wavelengths, providing information about electronic structure and bonding.

In summary, Erregung denotes a state of heightened energy due to external influence, and the related Erregungszustand or excited state refers to a higher-energy configuration across disciplines.