Bohr magneton

The value of the Bohr magneton
System of units	Value	Unit
SI^[1]	9.2740100657(29)×10⁻²⁴	J·T⁻¹
Gaussian^[2]	9.2740100783(28)×10⁻²¹	erg·G⁻¹
eV/T^[3]	5.7883818060(17)×10⁻⁵	eV·T⁻¹
atomic units	⁠1/2⁠	⁠eħ/m_e⁠

In atomic physics, the Bohr magneton (symbol $μ B$ ) is a physical constant and the natural unit for expressing the magnetic moment of an electron caused by its orbital or spin angular momentum.^[4]^[5] In SI units, the Bohr magneton is defined as $\mu _{\mathrm {B} }={\frac {e\hbar }{2m_{\mathrm {e} }}}$ and in the Gaussian CGS units as $\mu _{\mathrm {B} }={\frac {e\hbar }{2m_{\mathrm {e} }c}},$ where

$e$ is the elementary charge,
$ħ$ is the reduced Planck constant,
$m e$ is the electron mass,
$c$ is the speed of light.

^ "2022 CODATA Value: Bohr magneton". The NIST Reference on Constants, Units, and Uncertainty. NIST. May 2024. Retrieved 2024-05-18.
^ O'Handley, Robert C. (2000). Modern magnetic materials: principles and applications. John Wiley & Sons. p. 83. ISBN 0-471-15566-7. (value updated to correspond to CODATA 2018)
^ "CODATA value: Bohr magneton in eV/T". The NIST Reference on Constants, Units, and Uncertainty. NIST. Retrieved 2022-08-28.
^ Schiff, L. I. (1968). Quantum Mechanics (3rd ed.). McGraw-Hill. p. 440. ISBN 9780070856431.
^ Shankar, R. (1980). Principles of Quantum Mechanics. Plenum Press. pp. 398–400. ISBN 0306403978.

[physconst-muB-1] "2022 CODATA Value: Bohr magneton". The NIST Reference on Constants, Units, and Uncertainty. NIST. May 2024. Retrieved 2024-05-18.

[O'Handley_tati-2] O'Handley, Robert C. (2000). Modern magnetic materials: principles and applications. John Wiley & Sons. p. 83. ISBN 0-471-15566-7. (value updated to correspond to CODATA 2018)

[3] "CODATA value: Bohr magneton in eV/T". The NIST Reference on Constants, Units, and Uncertainty. NIST. Retrieved 2022-08-28.

[4] Schiff, L. I. (1968). Quantum Mechanics (3rd ed.). McGraw-Hill. p. 440. ISBN 9780070856431.

[5] Shankar, R. (1980). Principles of Quantum Mechanics. Plenum Press. pp. 398–400. ISBN 0306403978.

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