Niels Bohr applies quantum theory to Rutherford's atomic structure by assuming that electrons travel in stationary orbits defined by their angular momentum. This led to the calculation of possible energy levels for these orbits and the postulation that the emission of light occurs when an electron moves into a lower energy orbit.



Further info :

1911 Rutherford - Atomic Theory

Bohr model - http://csep10.phys.utk.edu/astr162/lect/light/bohr.html