Compton wavelength
Atomic & nuclearMeasured
= 2.426 310 235 38(76) × 10−12 m
- Value
- 2.426 310 235 38 × 10−12 m
- Standard uncertainty
- 7.6 × 10−22 m
- Relative uncertainty
- 3.1 × 10−10 (313 parts per trillion)
- Status
- Measured
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
# Compton wavelength, CODATA 2022 (NIST)
compton_wavelength = 2.42631023538e-12 # m, standard uncertainty 7.6e-22
# SciPy: scipy.constants.physical_constants['Compton wavelength']What it is
The wavelength of a photon whose energy equals the electron's rest energy. It sets the size of the wavelength shift when X-rays scatter off electrons: at 90° the shift is one Compton wavelength.
Equations
- definition
- Compton shift
In other units
| Unit | Value | |
|---|---|---|
| CGS (cm) | 2.426 310 235 38 × 10−10 | |
| nm nanometre | 0.002 426 310 235 38 | |
| pm picometre | 2.426 310 235 38 | |
| fm femtometre | 2426.310 235 38 | |
| Å ångström | 0.024 263 102 3538 | |
| a₀ bohr (atomic unit) | 0.045 850 618 41 | 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 | 2.426 310 235 38(76) × 10−12 | 3.1 × 10−10 | −4.5 σ of 2018 |
| 2018 | 2.426 310 238 67(73) × 10−12 | 3.0 × 10−10 | +1.8 σ of 2014 |
| 2014 | 2.426 310 2367(11) × 10−12 | 4.5 × 10−10 | −1.4 σ of 2010 |
| 2010 | 2.426 310 2389(16) × 10−12 | 6.6 × 10−10 | +6.5 σ of 2006 |
| 2006 | 2.426 310 2175(33) × 10−12 | 1.4 × 10−9 | −1.3 σ of 2002 |
| 2002 | 2.426 310 238(16) × 10−12 | 6.6 × 10−9 | +1.3 σ of 1998 |
| 1998 | 2.426 310 215(18) × 10−12 | 7.4 × 10−9 |
“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).