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The concept of free energy was developed by Hermann von Helmholtz, a German physicist, and first presented in 1882 in a lecture called "On the thermodynamics of chemical processes". [1] From the German word Arbeit (work), the International Union of Pure and Applied Chemistry (IUPAC) recommends the symbol A and the name Helmholtz energy. [2]
The Fermi energy for a three-dimensional, non-relativistic, non-interacting ensemble of identical spin-1 ⁄ 2 fermions is given by [1] = /, where N is the number of particles, m 0 the rest mass of each fermion, V the volume of the system, and the reduced Planck constant.
[11] [13] [14] [15] For materials with a direct band gap, valence electrons can be directly excited into the conduction band by a photon whose energy is larger than the bandgap. In contrast, for materials with an indirect band gap, a photon and phonon must both be involved in a transition from the valence band top to the conduction band bottom ...
In thermodynamics, the Gibbs free energy (or Gibbs energy as the recommended name; symbol ) is a thermodynamic potential that can be used to calculate the maximum amount of work, other than pressure–volume work, that may be performed by a thermodynamically closed system at constant temperature and pressure.
since / = 1.239 841 984... × 10 −6 eV⋅m [4] where h is the Planck constant, c is the speed of light, and e is the elementary charge. The photon energy of near infrared radiation at 1 μm wavelength is approximately 1.2398 eV.
Energy is a scalar quantity, and the mechanical energy of a system is the sum of the potential energy (which is measured by the position of the parts of the system) and the kinetic energy (which is also called the energy of motion): [1] [2]
Energy (from Ancient Greek ἐνέργεια (enérgeia) 'activity') is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light.
A 1 inch tall uranium fuel pellet is equivalent to about 1 ton of coal, 120 gallons of crude oil, or 17,000 cubic feet of natural gas. [15] In light-water reactors , 1 kg of natural uranium – following a corresponding enrichment and used for power generation– is equivalent to the energy content of nearly 10,000 kg of mineral oil or 14,000 ...