1. Spin and Atomic Physics 1. HW 8, problem 7.38 2. Quiz 11.6 3. Topics in this chapter:  The spin and the Stern-Gerlach experiment.  Fermion, Boson and the Pauli exclusion principle.  Multi-electron atoms and the Periodic Table.  Characteristic X-rays. Today

2. HW problem 7.38 Since it is an attractive central force and the angular momentum is given:    

3. The Stern-Gerlach experiment in the history of QM The Schrödinger Equation (1926): Electron discovered in by J.J. Thomson in 1897 Rutherford discovered nucleus in 1909 Niels Bohr’s Hydrogen model in 1913 The Balmer series 410 nm 434 nm 486 nm 656 nm Empirical formula in 1885: The de Broglie wave (1924): 1885 1897 1909 1913 1924 1926 1922 Stern-Gerlach experiment, electron spin in 1922

4. The Stern-Gerlach experiment Interesting to read: http://scitation.aip.org/journals/doc/PHTOAD-ft/vol_56/iss_12/53_1.shtml

5. The Stern-Gerlach experiment Classical Quantum WOW ! observed

6. The Stern-Gerlach experiment Quantum But: When ground state: From: But this was observed: WOW !!! What is this?

7. Spin, an intrinsic property Spin: an intrinsic magnetic dipole moment of particles like electron, proton and photons. This dipole moment is related to an intrinsic angular momentum. The symbol is S, which is like L the orbital angular momentum. The corresponding quantum number is s. The spin magnetic dipole moment is Spin is an intrinsic property of a particle like mass and charge. Example 8.1 electron

8. Fermions and Bosons Spin is an intrinsic property of a particle like mass and charge. FermionsBosons (half-integral spin)(integral spin) Particle s Electron, e - ½Pion, π 0 0 Proton, p½Alpha0 Neutron, n½Photon, γ1 Neutrino, ν ½ Deuteron, d1 Omega, Ω - ½ Graviton2

9. The building blocks for our Universe Spin is an intrinsic property of a particle like mass and charge.

10. The Pauli exclusion principle The Pauli exclusion principle (1924): No two indistinguishable fermions may occupy the same individual particle state. This principle applies only to fermions in In an atom, or an isolated system like a molecule. This principle does not apply to bosons.

11. Review questions What is the spin of a particle in CM and in QM? What is the spin of a particle in CM and in QM? Give one example in each the Pauli exclusion principle is applied. Give one example in each the Pauli exclusion principle is applied.

12. Preview for the next class (11/11) Text to be read: Text to be read: 8.4 and 8.5 8.4 and 8.5 Questions: Questions: Why we have H 2 as hydrogen molecules while Ne as neon molecules? Why we have H 2 as hydrogen molecules while Ne as neon molecules? What is the energy ordering of electron states in an atom with Z = 30? Can you fill the electrons for the element Zn if asked for? What is the energy ordering of electron states in an atom with Z = 30? Can you fill the electrons for the element Zn if asked for?

13. Homework 12, due by 11/13 Problems 8.28, 8.31 on page 339. Read section 8.2 and 8.3 one more time and see if you can answer questions in problem 8.7 on page 338.