Deuteron magnetic moment

$μ_d$ = 4.330 735 087(11) × 10⁻²⁷ J T⁻¹

Value: 4.330 735 087 × 10⁻²⁷ J T⁻¹
Standard uncertainty: 1.1 × 10⁻³⁵ J T⁻¹
Relative uncertainty: 2.5 × 10⁻⁹ (2.5 parts per billion)
Status: Measured
Symbol: $μ_d$
Source: CODATA 2022 via NIST · NIST entry

Use in a calculation

# deuteron magnetic moment, CODATA 2022 (NIST)
deuteron_magnetic_moment = 4.330735087e-27  # J T^-1, standard uncertainty 1.1e-35

# SciPy: scipy.constants.physical_constants['deuteron mag. mom.']

What it is

The magnetic moment of the deuteron, the nucleus of deuterium (one proton and one neutron): how strongly it behaves like a tiny bar magnet. A negative value means it points opposite to the spin.

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	4.330 735 087(11) × 10⁻²⁷	2.5 × 10⁻⁹	−0.6 σ of 2018
2018	4.330 735 094(11) × 10⁻²⁷	2.5 × 10⁻⁹	+1.5 σ of 2014
2014	0.433 073 5040(36) × 10⁻²⁶	8.3 × 10⁻⁹	+1.5 σ of 2010
2010	0.433 073 489(10) × 10⁻²⁶	2.3 × 10⁻⁸	+2.2 σ of 2006
2006	0.433 073 465(11) × 10⁻²⁶	2.5 × 10⁻⁸	−0.4 σ of 2002
2002	0.433 073 482(38) × 10⁻²⁶	8.8 × 10⁻⁸	+1.4 σ of 1998
1998	0.433 073 457(18) × 10⁻²⁶	4.2 × 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).