Hartree energy
Physical constant  

Surname  Hartree energy 
Formula symbol  
value  
SI  4th.359 744 722 2071 (85)e^{18} y 
Uncertainty (rel.)  1.9e^{12} 
Relation to other constants  
 Permittivity of the vacuum  Electron mass  Elementary charge  Planck's quantum of action 

Sources and Notes  
Source SI value: CODATA 2018 ( direct link ) 
The Hartree energy (after the English physicist Douglas Rayner Hartree ) is a physical constant that is used in atomic units as a unit of energy :
With
 the Planck constant
 the mass of the electron
 the Bohr radius
 the elementary charge
 the electric field constant
 the speed of light
 the fine structure constant .
The Hartree energy has twice the value of the unit Ry , which corresponds to the binding energy of the electron in the ground state of the hydrogen atom :
The numbers in brackets denote the uncertainty in the last digits of the value, this uncertainty is given as the estimated standard deviation of the specified numerical value from the actual value.
Related Hartree energies:
 on the amount of substance :
 on (useful for wave numbers in spectroscopy):
 .
Hartree defined the energy unit, which was later named after him, in his book The calculation of atomic structures as "mutual potential energy of two charge units that are at a unit distance from each other". As a load unit it has previously the amount of the charge of the electron, and as a unit of distance of the radius of the "first electron orbital of the hydrogen atom in the normal state", the Bohr radius is defined.
See also
 HartreeFock method (manybody systems)
Individual evidence
 ↑ CODATA Recommended Values. Hartree energy in eV E _{h} . National Institute of Standards and Technology, accessed July 20, 2019 .
 ↑ CODATA Recommended Values. Hartree energy E _{h} . National Institute of Standards and Technology, accessed July 20, 2019 .
 ↑ The thermochemical calorie 1 cal _{th} = 4.184 J was used to convert to kcal .
 ^ Douglas Rayner Hartree: The calculation of atomic structures . Wiley, New York, NY 1957 (IX, 181 S., Chapter ATOMIC UNITS on p. 5: "Unit of energy (...) the mutual potential energy of two unit charges at unit distance appart.").