Hartree
The hartree (symbol: E_{h} or Ha), also known as the Hartree energy, is the atomic unit of energy, named after the British physicist Douglas Hartree. It is defined as 2R_{∞}hc, where R_{∞} is the Rydberg constant, h is the Planck constant and c is the speed of light. The 2014 CODATA recommended value is E_{h} = 4.359 744 650(54)×10^{−18} J = 27.211 386 02(17) eV.^{[1]}
The hartree energy is approximately the electric potential energy of the hydrogen atom in its ground state and, by the virial theorem, approximately twice its ionization energy; the relationships are not exact because of the finite mass of the nucleus of the hydrogen atom and relativistic corrections.
The hartree is usually used as a unit of energy in atomic physics and computational chemistry: for experimental measurements at the atomic scale, the electronvolt (eV) or the reciprocal centimetre (cm^{−1}) are much more widely used.
Other relationships
where:
- ħ is the reduced Planck constant,
- m_{e} is the electron rest mass,
- e is the elementary charge,
- a_{0} is the Bohr radius,
- ε_{0} is the electric constant,
- c is the speed of light in vacuum, and
- α is the fine structure constant.
References
- ^ [1]