Hartree Energy

The natural energy unit of the hydrogen atom: twice its ionization energy.

Specifications & Metrics

symbol

Eh

status

Measured — CODATA 2022 adjustment

value

4.359744722206 × 10⁻¹⁸ ± 4.8 × 10⁻³⁰ J

Relative Scale in Constants

Core Principles & Analysis

• About 27.2 eV, the absolute unit of atomic physics and quantum chemistry.
• Atomic units measure everything in Hartrees, Bohr radii and electron masses.
• Half a Hartree is the ground-state energy of hydrogen in the Bohr model.