Atomic unit of charge
UnitsExact
= 1.602 176 634 × 10−19 C
- Value
- 1.602 176 634 × 10−19 C
- Standard uncertainty
- exact
- Relative uncertainty
- exact
- Status
- Exact since the 2019 SI redefinition
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
# atomic unit of charge, CODATA 2022 (NIST)
atomic_unit_of_charge = 1.602176634e-19 # C, exact
# SciPy: scipy.constants.physical_constants['atomic unit of charge']What it is
The unit of charge 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.
It is built only from constants that have exact values since 20 May 2019, so it is exact too; CODATA 2018 was the first adjustment to list it that way.
In other units
| Unit | Value | |
|---|---|---|
| e elementary charge | 1 | exact |
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.
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). Diamonds mark adjustments in which the value was exact.
Relative uncertainty
| CODATA | Value (uncertainty) | Relative uncertainty | Change from previous |
|---|---|---|---|
| 2022 | 1.602 176 634 × 10−19 | exact | exact |
| 2018 | 1.602 176 634 × 10−19 | exact | +1.3 σ of 2014 |
| 2014 | 1.602 176 6208(98) × 10−19 | 6.1 × 10−9 | +1.6 σ of 2010 |
| 2010 | 1.602 176 565(35) × 10−19 | 2.2 × 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).