Atomic unit of electric field gradient
UnitsMeasured
= 9.717 362 4424(30) × 1021 V m−2
- Value
- 9.717 362 4424 × 1021 V m−2
- Standard uncertainty
- 3 × 1012 V m−2
- Relative uncertainty
- 3.1 × 10−10 (309 parts per trillion)
- Status
- Measured
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
Plain
LaTeX
Python
# atomic unit of electric field gradient, CODATA 2022 (NIST)
atomic_unit_of_electric_field_gradient = 9.7173624424e21 # V m^-2, standard uncertainty 3e12
# SciPy: scipy.constants.physical_constants['atomic unit of electric field gradient']What it is
The unit of electric field gradient 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).
Relative uncertainty
| CODATA | Value (uncertainty) | Relative uncertainty | Change from previous |
|---|---|---|---|
| 2022 | 9.717 362 4424(30) × 1021 | 3.1 × 10−10 | +4.6 σ of 2018 |
| 2018 | 9.717 362 4292(29) × 1021 | 3.0 × 10−10 | +1.2 σ of 2014 |
| 2014 | 9.717 362 356(60) × 1021 | 6.2 × 10−9 | +1.7 σ of 2010 |
| 2010 | 9.717 362 00(21) × 1021 | 2.2 × 10−8 | +1.4 σ of 2006 |
| 2006 | 9.717 361 66(24) × 1021 | 2.5 × 10−8 | −0.2 σ of 2002 |
| 2002 | 9.717 361 82(83) × 1021 | 8.5 × 10−8 | +0.7 σ of 1998 |
| 1998 | 9.717 361 53(39) × 1021 | 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).