Materie & Energie

Energieverteilung | Physik

Equipartition of energy, law of statistical mechanics stating that, in a system in thermal equilibrium, on the average, an equal amount of energy will be associated with each independent energy state. Based on the work of physicists James Clerk Maxwell of Scotland and Ludwig Boltzmann of Germany, this law states specifically that a system of particles in equilibrium at absolute temperature T will have an average energy of 1/2kT associated with each degree of freedom (see freedom, degree of), in which k ist die Boltzmann-Konstante . Darüber hinaus werden alle Freiheitsgrad beitragen potentielle Energie wird eine weitere 1 / 2 kT mit ihm verbunden ist . Für ein System von s Freiheitsgraden, von denen t potentiellen Energien zugeordnet sind, ist die Gesamtdurchschnittsenergie des Systems 1 / 2 ( s + t ) kT .

For example, an atom of a gas has three degrees of freedom (the three spatial, or position, coordinates of the atom) and will, therefore, have an average total energy of 3/2kT. For an atom in a solid, vibratory motion involves potential energy as well as kinetic energy, and both modes will contribute a term 1/2kT, resulting in an average total energy of 3kT.