Rydberg constant times hc in J
Atomic & nuclearMeasured
= 2.179 872 361 1030(24) × 10−18 J
- Value
- 2.179 872 361 1030 × 10−18 J
- Standard uncertainty
- 2.4 × 10−30 J
- Relative uncertainty
- 1.1 × 10−12 (1.1 parts per trillion)
- Status
- Measured
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
# Rydberg constant times hc in J, CODATA 2022 (NIST)
rydberg_constant_times_hc_in_j = 2.179872361103e-18 # J, standard uncertainty 2.4e-30
# SciPy: scipy.constants.physical_constants['Rydberg constant times hc in J']What it is
The Rydberg energy R∞hc in joules: the ionisation energy of hydrogen in the heavy-nucleus limit, about 13.6 eV.
In other units
| Unit | Value | |
|---|---|---|
| CGS (cm2 g s−2) | 2.179 872 3611 × 10−11 | |
| eV electronvolt | 13.605 693 123 | |
| keV kiloelectronvolt | 0.013 605 693 123 | |
| Eₕ hartree | 0.5 | unit is itself measured |
| Ry rydberg | 1 | unit 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).
Relative uncertainty
| CODATA | Value (uncertainty) | Relative uncertainty | Change from previous |
|---|---|---|---|
| 2022 | 2.179 872 361 1030(24) × 10−18 | 1.1 × 10−12 | −0.1 σ of 2018 |
| 2018 | 2.179 872 361 1035(42) × 10−18 | 1.9 × 10−12 | +1.3 σ of 2014 |
| 2014 | 2.179 872 325(27) × 10−18 | 1.2 × 10−8 | +1.6 σ of 2010 |
| 2010 | 2.179 872 171(96) × 10−18 | 4.4 × 10−8 | +1.8 σ of 2006 |
| 2006 | 2.179 871 97(11) × 10−18 | 5.0 × 10−8 | −0.3 σ of 2002 |
| 2002 | 2.179 872 09(37) × 10−18 | 1.7 × 10−7 | +1.1 σ of 1998 |
| 1998 | 2.179 871 90(17) × 10−18 | 7.8 × 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).