relaxationen

Relaxationen is the plural of Relaxation in German, and is used across multiple scientific disciplines to describe processes by which a system returns to thermal or mechanical equilibrium after a disturbance.

In physics and physical chemistry, relaxation processes are typically characterized by a relaxation time, a timescale that governs how quickly a quantity such as a population, a population difference, or a macroscopic observable approaches its equilibrium value. Many relaxation phenomena follow exponential decay, while more complex systems may exhibit stretched or multi-exponential behavior.

In mechanical contexts, stress relaxation refers to the decrease of internal stress in a material kept at constant strain, common in viscoelastic polymers and rubbers. This contrasts with creep, where strain increases under constant stress. Rheological models, such as the Maxwell or Kelvin–Voigt frameworks, aim to describe relaxation behavior through combinations of springs and dashpots.

Thermal and chemical relaxation describes how a system exchanges energy with its surroundings and relaxes to thermal equilibrium after heating or irradiation. Molecular relaxation includes vibrational and rotational cooling and internal conversion, while in spectroscopy, spin-lattice (T1) and spin-spin (T2) relaxation times describe how nuclear or electronic spins lose coherence or return to equilibrium.

In statistical mechanics and soft matter, relaxation times appear in correlation functions and response functions, indicating how rapidly fluctuations decay. Near critical points, relaxation can slow dramatically, a phenomenon known as critical slowing down.

Applications span condensed matter, polymers, liquids, plasmas, and biological systems. Experimental methods include rheology, calorimetry, spectroscopy, and magnetic resonance techniques, all aimed at quantifying relaxation times and mechanisms.