ConstantID

Hartree energy in eV

Atomic & nuclearMeasured

Eh = 27.211 386 245 981(30) eV

Value
27.211 386 245 981 eV
Standard uncertainty
3 × 10−11 eV
Relative uncertainty
1.1 × 10−12 (1.1 parts per trillion)
Status
Measured
Symbol
Eh
Source
CODATA 2022 via NIST · NIST entry

Use in a calculation

# Hartree energy in eV, CODATA 2022 (NIST)
hartree_energy_in_ev = 2.7211386245981e1  # eV, standard uncertainty 3e-11

# SciPy: scipy.constants.physical_constants['Hartree energy in eV']

What it is

The Hartree energy expressed in electronvolts.

In other units

UnitValue
CGS (cm2 g s−2)4.359 744 722 21 × 10−11
keV kiloelectronvolt0.027 211 386 246
Eₕ hartree1unit is itself measured
Ry rydberg2unit is itself measured

Converted with ConstantID's unit table; digits are rounded to the precision of the value, and a long exact value is rounded only for display. The relative uncertainty is unchanged by conversion to an exactly defined unit.

How the value changed, 1998–2022

Each point is one CODATA adjustment, plotted as its difference from the 2022 value; the bars show one standard uncertainty (an arrowhead means the bar runs off the chart).

Hartree energy in eV: CODATA values 1998–2022 relative to the 2022 value, in parts per billion, with one-standard-uncertainty bars−150−100−500+50+100+150parts per billion1998200220062010201420182022

Relative uncertainty

Hartree energy in eV: relative standard uncertainty in each CODATA adjustment, logarithmic scale10⁻¹²10⁻¹¹10⁻¹⁰10⁻⁹10⁻⁸10⁻⁷1998200220062010201420182022
CODATAValue (uncertainty)Relative uncertaintyChange from previous
202227.211 386 245 981(30)1.1 × 10−12 −0.1 σ of 2018
201827.211 386 245 988(53)1.9 × 10−12 +1.3 σ of 2014
201427.211 386 02(17)6.2 × 10−9 +1.6 σ of 2010
201027.211 385 05(60)2.2 × 10−8 +1.8 σ of 2006
200627.211 383 86(68)2.5 × 10−8 −0.3 σ of 2002
200227.211 3845(23)8.5 × 10−8 +1.0 σ of 1998
199827.211 3834(11)4.0 × 10−8

“Change from previous” is the shift in the value divided by the standard uncertainty of the previous adjustment. Earlier values are converted into the current unit where NIST changed it (for example J s to J Hz⁻¹).

Related constants

Atomic & nuclear a0 Bohr radius 5.291 772 105 44(82) × 10−11 m Atomic & nuclear re Classical electron radius 2.817 940 3205(13) × 10−15 m Atomic & nuclear λC Compton wavelength 2.426 310 235 38(76) × 10−12 m Atomic & nuclear α Fine-structure constant 7.297 352 5643(11) × 10−3 Atomic & nuclear Eh Hartree energy 4.359 744 722 2060(48) × 10−18 J Atomic & nuclear α−1 1/α 137.035 999 177(21) Atomic & nuclear πℏ/me Quantum of circulation 3.636 947 5467(11) × 10−4 m2 s−1 Atomic & nuclear h/me Quantum of circulation times 2 7.273 895 0934(23) × 10−4 m2 s−1