ConstantID

Atomic unit of current

UnitsMeasured

eEh/ℏ = 6.623 618 237 5082(72) × 10−3 A

Value
6.623 618 237 5082 × 10−3 A
Standard uncertainty
7.2 × 10−15 A
Relative uncertainty
1.1 × 10−12 (1.1 parts per trillion)
Status
Measured
Symbol
eEh/ℏ
Source
CODATA 2022 via NIST · NIST entry

Use in a calculation

# atomic unit of current, CODATA 2022 (NIST)
atomic_unit_of_current = 6.6236182375082e-3  # A, standard uncertainty 7.2e-15

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

What it is

The unit of current 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.

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 current: 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 current: relative standard uncertainty in each CODATA adjustment, logarithmic scale10⁻¹²10⁻¹¹10⁻¹⁰10⁻⁹10⁻⁸10⁻⁷1998200220062010201420182022
CODATAValue (uncertainty)Relative uncertaintyChange from previous
20226.623 618 237 5082(72) × 10−31.1 × 10−12 −0.1 σ of 2018
20186.623 618 237 510(13) × 10−32.0 × 10−12 +1.3 σ of 2014
20146.623 618 183(41) × 10−36.2 × 10−9 +1.6 σ of 2010
20106.623 617 95(15) × 10−32.3 × 10−8 +1.9 σ of 2006
20066.623 617 63(17) × 10−32.6 × 10−8 −0.3 σ of 2002
20026.623 617 82(57) × 10−38.6 × 10−8 +1.1 σ of 1998
19986.623 617 53(26) × 10−33.9 × 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).