|Themes > Science > Physics > Atomic Physics > Spin| In particle
and atomic physics, there are two types of angular momentum:
spin and orbital angular momentum: 1. Spin is a fundamental
property of all elementary particles, and is present even if the
particle is not moving: 2. Orbital angular momentum results from
the motion of a particle. For example, an electron in an atom
has orbital angular momentum, which results from the electron's
motion about the nucleus, and spin angular momentum. The total
angular momentum of a particle is a combination of spin and
orbital angular momentum. The existence of spin was suggested by
the Dutch-born American physicists Samuel Abraham Goudsmit and
George Eugene Uhlenbeck in 1925. The two physicists noted that
certain features of the atomic spectra could not be explained by
the quantum theory in use at the time. By adding an additional
quantum number-the spin of the electron-Goudsmit and Uhlenbeck
were able to provide a more complete explanation of atomic
spectra. Soon the