reduced Planck constant
Angular momentumexact by definition
The reduced Planck constant is the Planck constant divided by 2π, about 1.054571817 × 10⁻³⁴ J·s. It is the natural quantum of angular momentum: electron spin is one half of it, orbital angular momentum comes in integer multiples of it, and it is the constant that actually appears in the Schrödinger equation and the uncertainty principle.
Watch out: Physics writes it with a barred h, which has no metrics in the fonts this site typesets unit symbols with, so the symbol here is spelled out. Its value is exact in the sense that h is exact and 2π is a number, though its decimal expansion never terminates. Do not confuse it with h itself, which is 6.283 times larger.
| 1 | 1.0545718e-34 |
One reduced planck constant in every angular momentum unit
| 1 | reduced Planck constant (hbar)this unit | |
| 0.159155 | Planck constant (h) | |
| 1.05457e-27 | gram square centimeter per second (g·cm²/s) | |
| 1.05457e-27 | erg second (erg·s) | |
| 1.05457e-30 | kilogram square centimeter per second (kg·cm²/s) | |
| 2.50254e-33 | pound square foot per second (lb·ft²/s) | |
| 1.05457e-34 | kilogram square meter per second (kg·m²/s) | |
| 1.05457e-34 | joule second (J·s) | |
| 1.05457e-34 | newton meter second (N·m·s) | |
| 7.77812e-35 | slug square foot per second (slug·ft²/s) |
Solvers that use angular momentum