Phasenübergangsnukleation

Phasenübergang, also known as phase transition, refers to the physical process of a substance changing from one state of matter to another. These transitions occur at specific temperatures and pressures. The most common examples involve transitions between solid, liquid, and gaseous states.

A solid melting into a liquid is called fusion. The reverse process, a liquid solidifying, is called solidification or freezing. Evaporation or boiling is the transition from liquid to gas. Condensation is the opposite, where a gas turns back into a liquid. Sublimation is the direct transition from solid to gas, bypassing the liquid phase, while deposition is the reverse process.

These transitions are accompanied by changes in the substance's energy. For example, energy must be absorbed for melting and evaporation, while energy is released during freezing and condensation. The temperature at which a phase transition occurs at a given pressure is known as the transition point, such as the melting point or boiling point.

Beyond the familiar states, phase transitions also occur in more complex systems. In physics, this includes phenomena like magnetic phase transitions, superconductivity, and Bose-Einstein condensation. These transitions are often characterized by changes in the macroscopic properties of the material, even though the underlying particles remain the same. The study of phase transitions is a fundamental part of thermodynamics and statistical mechanics.