Bohr radius
Bohr's model of the hydrogen atom, the Bohr radius (<math>a_0<math>) is the radius of the lowest energy orbit:
<math>a_0 = {{4\pi\epsilon_0\hbar^2}\over{m_e e^2}}<math>
where:
- <math>\epsilon_0<math> is the permittivity of vacuum
- <math>\hbar<math> is the reduced Planck's constant
- <math>m_e<math> is the electron rest mass
and
- <math>e<math> is the elementary charge
It has a value of 5.29189379×10-11 m, about 53 picometers (or about half an angstrom).
The Bohr radius is often used as a unit in atomic physics, typically in perturbative expansions of wave function solutions.
