Hartreeyksiköt

Hartreeyksiköt, also known as Hartree units or atomic units of energy, are a system of natural units used in atomic physics and chemistry. They are derived from fundamental constants of nature, making them particularly convenient for calculations involving atomic and molecular systems. The base unit of energy in this system is the Hartree, which is equivalent to the magnitude of the potential energy of an electron in a hydrogen atom at its ground state. Specifically, one Hartree is equal to $e^2 / (4\pi\epsilon_0 a_0)$, where $e$ is the elementary charge, $\epsilon_0$ is the permittivity of free space, and $a_0$ is the Bohr radius.

The Hartree unit system simplifies many equations in quantum mechanics by setting several fundamental constants to unity. For instance, the electron's mass, the elementary charge, the reduced Planck constant, and the Coulomb constant are all set to 1 in the system of Hartree atomic units. This normalization eliminates the need to repeatedly include these constants in theoretical calculations, leading to more streamlined and conceptually clear results. The Hartree unit of energy is approximately 4.3597477 x 10^-18 joules, or 27.211386 electron volts. This system is widely adopted in computational chemistry and condensed matter physics for its elegance and practicality in theoretical treatments.