Electron gyromagnetic ratio in MHz/T

$γₑ/2π$ = 28 024.951 3861(87) MHz T⁻¹

Value: 28 024.951 3861 MHz T⁻¹
Standard uncertainty: 8.7 × 10⁻⁶ MHz T⁻¹
Relative uncertainty: 3.1 × 10⁻¹⁰ (310 parts per trillion)
Status: Measured
Symbol: $γₑ/2π$
Source: CODATA 2022 via NIST · NIST entry

Use in a calculation

# electron gyromagnetic ratio in MHz/T, CODATA 2022 (NIST)
electron_gyromagnetic_ratio_in_mhz_t = 2.80249513861e4  # MHz T^-1, standard uncertainty 8.7e-6

# SciPy: scipy.constants.physical_constants['electron gyromag. ratio in MHz/T']

What it is

The precession frequency, per tesla of magnetic field, of the electron, the lightest charged particle and the carrier of electric current in metals: the gyromagnetic ratio divided by 2π. Magnetic resonance spectroscopists use this form.

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	28 024.951 3861(87)	3.1 × 10⁻¹⁰	−4.5 σ of 2018
2018	28 024.951 4242(85)	3.0 × 10⁻¹⁰	−1.3 σ of 2014
2014	28 024.951 64(17)	6.1 × 10⁻⁹	−1.6 σ of 2010
2010	28 024.952 66(62)	2.2 × 10⁻⁸	−1.4 σ of 2006
2006	28 024.953 64(70)	2.5 × 10⁻⁸	+0.2 σ of 2002
2002	28 024.9532(24)	8.6 × 10⁻⁸	−0.7 σ of 1998
1998	28 024.9540(11)	3.9 × 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).