Hartree

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The hartree (symbol: Eh 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 2Rhc, where R is the Rydberg constant, h is the Planck constant and c is the speed of light. The 2006 CODATA recommended value is Eh = 4.359 743 94 (22)×10−18 J = 27.211 383 86 (68) eV.[1] The 2010 CODATA recommended value is Eh = 4.359 744 34 (10)×10−18 J.

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

= 2 Ry
≜ 4.359 743 94 (22)×10−18 J
≜ 27.211 383 86 (68) eV
≜ 2625.499 62 kJ/mol
≜ 627.509 469 kcal/mol
≜ 219 474.631 3705(15) cm−1
≜ 6 579.683 920 729(33) THz

where:

ħ is the reduced Planck constant,
me is the electron rest mass,
e is the elementary charge,
a0 is the Bohr radius,
ε0 is the electric constant,
c is the speed of light in vacuum, and
α is the fine structure constant.

References

  1. ^ Mohr, Peter J.; Taylor, Barry N.; Newell, David B. (2008). "CODATA Recommended Values of the Fundamental Physical Constants: 2006" (PDF). Reviews of Modern Physics. 80 (2): 633–730. arXiv:0801.0028. Bibcode:2008RvMP...80..633M. doi:10.1103/RevModPhys.80.633. Archived from the original (PDF) on 2017-10-01. Direct link to value..