ConstantID

Deuteron relative atomic mass

Atomic & nuclearMeasured

Ar(d) = 2.013 553 212 544(15)

Value
2.013 553 212 544
Standard uncertainty
1.5 × 10−11
Relative uncertainty
7.4 × 10−12 (7.4 parts per trillion)
Status
Measured
Symbol
Ar(d)
Source
CODATA 2022 via NIST · NIST entry

Use in a calculation

# deuteron relative atomic mass, CODATA 2022 (NIST)
deuteron_relative_atomic_mass = 2.013553212544  # standard uncertainty 1.5e-11

# SciPy: scipy.constants.physical_constants['deuteron relative atomic mass']

What it is

The mass of the deuteron, the nucleus of deuterium (one proton and one neutron), divided by the atomic mass constant (one twelfth of the mass of a carbon-12 atom). It has no 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).

deuteron relative atomic mass: CODATA values 1998–2022 relative to the 2022 value, in parts per trillion, with one-standard-uncertainty bars−150−100−500+50+100+150parts per trillion1998200220062010201420182022

Relative uncertainty

deuteron relative atomic mass: relative standard uncertainty in each CODATA adjustment, logarithmic scale10⁻¹²10⁻¹¹10⁻¹⁰1998200220062010201420182022
CODATAValue (uncertainty)Relative uncertaintyChange from previous
20222.013 553 212 544(15)7.4 × 10−12 −5.0 σ of 2018
20182.013 553 212 745(40)2.0 × 10−11

“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).

Related constants

Atomic & nuclear μd/μe Deuteron-electron magnetic moment ratio −4.664 345 550(12) × 10−4 Atomic & nuclear md/me Deuteron-electron mass ratio 3670.482 967 655(63) Atomic & nuclear gd Deuteron g factor 0.857 438 2335(22) Atomic & nuclear μd Deuteron magnetic moment 4.330 735 087(11) × 10−27 J T−1 Atomic & nuclear μd/μB Deuteron magnetic moment to Bohr magneton ratio 4.669 754 568(12) × 10−4 Atomic & nuclear μd/μN Deuteron magnetic moment to nuclear magneton ratio 0.857 438 2335(22) Atomic & nuclear md Deuteron mass 3.343 583 7768(10) × 10−27 kg Atomic & nuclear mdc2 Deuteron mass energy equivalent 3.005 063 234 91(94) × 10−10 J