Atomic unit of velocity = 2.187 691 262 16 × 10⁶ m·s⁻¹

Name: Atomic unit of velocity — CODATA 2022 value
Creator: NIST

Value: 2.187 691 262 16 × 10⁶
Unit: m·s⁻¹
Uncertainty: 0.000 000 000 34 × 10⁶
Copy-ready: 2.18769126216e6

The atomic unit of velocity: the natural size of velocity in the Hartree system, where ℏ, e, mₑ and 4πε₀ all equal 1.

Quantum-chemistry and atomic-physics codes report velocity in atomic units; multiply a result by this value to get it in SI.

NIST, Fundamental Physical Constants — Complete Listing (2022 CODATA adjustment), retrieved 2026-07-26.

Atomic units

Atomic unit of 1st hyperpolarizability Atomic unit of 2nd hyperpolarizability Atomic unit of charge density Atomic unit of current Atomic unit of electric dipole moment Atomic unit of electric field Atomic unit of electric field gradient Atomic unit of electric polarizability Atomic unit of electric potential Atomic unit of electric quadrupole moment Atomic unit of force Atomic unit of magnetic dipole moment Atomic unit of magnetic flux density Atomic unit of magnetizability Atomic unit of momentum Atomic unit of permittivity Atomic unit of time Atomic unit of velocity

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UsePhysics. "Atomic unit of velocity — 2.187 691 262 16 × 106 m·s⁻¹." UsePhysics.com. https://usephysics.com/reference/atomic-unit-of-velocity. Value from the 2022 CODATA adjustment (NIST). Accessed [date].

Atomic units

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