Atomic units
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The atomic units, abbreviated a.u. is a set of units used in atomic calculations.[1][2]
Base units
| Atomic base units [2] | |||
|---|---|---|---|
| Name | Symbol | Quantity | Value in SI units |
| elementary charge | e | charge | 1.602 176 53(14) × 10−19 C |
| Bohr radius (bohr) | a0 | length | 0.529 177 2108(18) × 10−10 m |
| electron mass | me | mass | 9.109 3826(16) × 10−31 kg |
| Reduced period of first Bohr orbit | ℏ/Eh | time | 2.418 884 326 505(16) × 10−17 s |
| Reduced Planck constant | ℏ | action | 1.054 571 68(18) × 10−34 Js |
| Hartree energy (hartree) | Eh | energy | 4.359 744 17(75) × 10−18 J |
| a.u. velocity | vB≡αc | velocity | 2.187 691 2633(73) × 106 m/s |
Here, c = speed of light and α = fine structure constant.
Notes
- ↑ For an introduction, see Gordon W. F. Drake (2006). “§1.2 Atomic units”, Springer handbook of atomic, molecular, and optical physics, Volume 1, 2nd ed. Springer, p. 6. ISBN 038720802X.
- ↑ 2.0 2.1 Tabulated values from Barry N. Taylor (2008). International System of Units (SI), Revised 2008 ed. DIANE Publishing, Table 7, p.33. ISBN 1437915582.