Total energy
In quantum physics and thermodynamics, the total energy of a system is the energy difference between the system and its components at an infinite distance .
For example, the total energy of a molecule is the energy difference between the molecule in a given state and the hypothetical state in which all the electrons and atomic nuclei that make up it are infinitely far apart.
The total energy is not a clear variable, but it is of great importance in the quantum mechanical analysis of molecules and solids whose Schrödinger equations are approximated by approximation methods , e.g. B. Hartree-Fock , density functional theory , MP2 , can be solved. The smaller the total energies in these approximate solutions, the closer they are to the exact solution of the differential equation , since according to the Rayleigh-Ritz principle the total energy of the exact solution is always less than or equal to the total energy of an approximate solution.
In relativistic mechanics , the total energy of a particle is the sum of its rest energy and its kinetic energy .
In classical mechanics , according to the law of conservation of energy, the total energy consists of the kinetic energy and the potential energy . In continuum mechanics , the deformation energy is added.
Individual evidence
- ↑ Torsten Fließbach: Mechanics . Textbook on Theoretical Physics I. 7th edition. Springer-Spektrum, 2015, ISBN 978-3-642-55431-5 ( limited preview in the Google book search).
- ↑ H. Altenbach: Continuum Mechanics: Introduction to the material-independent and material-dependent equations . 3. Edition. Springer-Vieweg, 2015, ISBN 978-3-662-47069-5 , doi : 10.1007 / 978-3-662-47070-1 ( limited preview in Google book search [accessed April 1, 2018]).