Result of the Stern-Gerlach Experiment

 

 

The Stern-Gerlach experiment is one of the experiments that best demonstrates the reality of quantum physics. In 1922, Otto Stern and Walther Gerlach devised a highly effective experiment to test Bohr's theory of discrete angular momentum. Let's take an in-depth look at the experimental setup below.

Stern and Gerlach used Ag atoms with 47 atoms to perform this experiment. Ag atoms with 47 atoms have 5s¹ unpaired electrons in their final orbital orbitals.

Ag atoms are heated in a furnace to give them high energy. Ag atoms with high energy spins oriented in different directions are passed through the collimators in bunches and then in an inhomogeneous magnet and hit the observation screen. There are two important points here.

One of these important points is that an inhomogeneous magnet was used in the experiment. As you can see in the setup, the N pole is wide and the S pole has pointed ends. The magnetic field lines are more intense at the pointed end of the S pole.

If the dipole moment of the electrons is oriented in the same direction as the externally applied inhomogeneous magnetic field, the potential energy of the particles becomes minimum and the particles are directed towards the S pole. However, the potential energy of the particles is maximum if the dipole moment is not in the same direction as the externally applied inhomogeneous magnetic field. Since nature tends to have minimum energy, our particles will be oriented toward the N pole.

The second important point is that when we think classically, we could expect that we would observe a continuous distribution on the observation screen since we thought that the spins of Ag

The second important point is that when we think classically, we could expect that we would observe a continuous distribution on the observation screen since we thought that the spins of Ag atoms circulating in the furnace with the Boltzmann distribution would have every value. atoms circulating in the furnace with the Boltzmann distribution would have every value.

However, the Stern-Gerlach experiment clearly showed that after passing through the inhomogeneous magnet leaving the furnace, the spins of the Ag electrons make two intermittent peaks. As a result, it was understood that the spins were quantized. Thanks to this important information, it has been possible to understand the working logic of quantum and improve its applications.

Reference

https://www.researchgate.net/figure/Energy-level-diagram-of-an-S1-2-moment-in-a-magnetic-field-B_fig28_263685155

Weinert, F. (1995). "Wrong theory—right experiment: The significance of the Stern–Gerlach experiments". Studies in History and Philosophy of Modern Physics. 26B: 75–86.