1. Quantum mechanics I Fall 2012
Physics 451
Quantum mechanics I
Fall 2012
Nov 28, 2012
Karine Chesnel

2. Tuesday Nov 27 – Friday Nov 30
Quantum mechanics
Test 3
Tuesday Nov 27 – Friday Nov 30
Homework
HW 22 Thur Nov 29, 7pm
HW 23 Tuesday Dec 4 , 7pm
HW 24 Thursday Dec 6, 7pm 5

3. Exchange forces Attraction force Symmetrical state: Covalent bound
Quantum mechanics
Exchange forces
Attraction force
Symmetrical state:
Covalent bound
Repulsion force
Antisymmetrical state

4. Two electrons Total state antisymmetrical Spin state: singulet
Quantum mechanics
Two electrons
Total state antisymmetrical
Spatial state symmetrical
Spin state: singulet
antisymmetrical
Attraction force
Covalent bound
Pb 5.6

5. Quiz 29a If two electrons would occupy a triplet state (S=1)
Quantum mechanics
Quiz 29a
If two electrons would occupy a triplet state (S=1)
what can we say about their spatial wave function?
It is antisymmetric (antibounding)
It is symmetric (bounding)
It could be both

6. Homework Pb 5.1: Pb 5.2: Pb 5.6: Quantum mechanics Reduced coordinates

7. Quantum mechanics
Atoms e-
Z=2 e-
Helium
Z=1
Hydrogen

8. Helium e- e- Quantum mechanics r2 r1 Z=2 electron 1
in the nucleus potential
electron 2
in the nucleus potential
Interaction
between
electrons 1 & 2 11

9. Helium Quantum mechanics To a first order: electron 2 electron 1
in the nucleus potential
electron 1
in the nucleus potential 12

10. Helium Quantum mechanics Ground state: In this approximation:
Difference comes from
the missing term
In the potential
Experimentally: 13

11. Quantum mechanics
Helium E
Excited states: 14

12. Helium Symmetrization requirements
Quantum mechanics
Helium Symmetrization requirements
Total state antisymmetric (electrons)
Spatial wave function
Spin state
Parahelium
Singlet : antisymmetric
Symmetric
Orthohelium
Triplet : symmetric
Antisymmetric

13. Quantum mechanics
Helium Energy levels

14. Quiz 29b Which of these states corresponds to the energy
Quantum mechanics
Quiz 29b
Which of these states corresponds to the energy
Level 3P in 3P Orthohelium ? A. B. C. D. E. 17