ConstantID

Atomic unit of electric potential

UnitsMeasured

Eh/e = 27.211 386 245 981(30) V

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

Use in a calculation

# atomic unit of electric potential, CODATA 2022 (NIST)
atomic_unit_of_electric_potential = 2.7211386245981e1  # V, standard uncertainty 3e-11

# SciPy: scipy.constants.physical_constants['atomic unit of electric potential']

What it is

The unit of electric potential in the Hartree system of atomic units, where the electron mass, the elementary charge, ħ and 4πε₀ are all set to 1. Its value here is the SI equivalent of one atomic unit.

In other units

UnitValue
mV millivolt27 211.386 246
kV kilovolt0.027 211 386 246
statV statvolt0.090 767 414 3223

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).

atomic unit of electric potential: 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

atomic unit of electric potential: 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).