Thermalisation
Encyclopedia
In physics
, thermalisation (in American English thermalization) is the process of particles reaching thermal equilibrium
through mutual interaction.
When a molecule absorbs energy, as in the technique of molecular fluorescence, the lifetime of the excited state is ~10−12 sec. Then it rapidly loses energy to the lowest level of the lowest excited state; this is called thermalization.
In general the natural tendency of a system is towards a state of equipartition of energy or uniform temperature.
This raises the system’s entropy
.
Examples of thermalisation include:
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, thermalisation (in American English thermalization) is the process of particles reaching thermal equilibrium
Thermal equilibrium
Thermal equilibrium is a theoretical physical concept, used especially in theoretical texts, that means that all temperatures of interest are unchanging in time and uniform in space...
through mutual interaction.
When a molecule absorbs energy, as in the technique of molecular fluorescence, the lifetime of the excited state is ~10−12 sec. Then it rapidly loses energy to the lowest level of the lowest excited state; this is called thermalization.
In general the natural tendency of a system is towards a state of equipartition of energy or uniform temperature.
This raises the system’s entropy
Entropy
Entropy is a thermodynamic property that can be used to determine the energy available for useful work in a thermodynamic process, such as in energy conversion devices, engines, or machines. Such devices can only be driven by convertible energy, and have a theoretical maximum efficiency when...
.
Examples of thermalisation include:
- the achievement of equilibrium in a plasmaPlasma (physics)In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
- the process undergone by high-energy neutrons as they lose energy by collision with a moderatorNeutron moderatorIn nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235....
.