## Atomic Structure in Quantum Mechanics

Bohr arrived at these "stationary states" by requiring a quantization of the

angular momentum.If we look at the deBroglie wavelength of an electron for these various energies, we find that it "fits" the allowed orbits with an integral number of wavelengths--leading to

constructiveinterference much like standing waves on a rope.But a

betterpicture is that of an "electron cloud" surrounding the nucleus with the "density" of the cloud connected to the probability of finding the electron.Energy is quantized. The n in E

_{n}is called theprincipal quantum number.So are other quantities.

Angular Momentumis called the

orbital quantum number.

z-compent of angular momentum

is called the

magnetic quantum number.The

intrinsic angular momentumof the electron, often call the electron'sspin, isThe

z-componentof thespinof the electron is

(c) Doug Davis, 1997; all rights reserved