1. Particles and Waves

2. Blackbody Radiation Stephan-Boltzman Law T4 Radiance T3 T2 T1
wavelength

3. Wien’s Law & Blackbody Radiance
Wavelength
Intensity
6000K
4000K
700nm
400nm
Visible IR UV

4. Photons Light consists of packets or quanta of energy.v
Light consists of packets or quanta of energy.
Heisenberg’s Uncertainty Principle l v

5. Photoelectric Effect
Electrons are emitted when light is incident on certain metals. IR
l=1.0×10-5m UV e- e-
l=1.0×10-7m

6. Atomic Spectra Emission Absorption Hydrogen
Specific wavelengths added by hot gas.
Absorption
Specific wavelengths removed by cold gas.
Hydrogen
Helium
Carbon
Oxygen

7. Bohr Model of Hydrogen Electrons move in circular orbits
Only certain orbits are stable
Radiation emitted or absorbed as electron moves from one orbit to another
Allowed orbits determined by quantized angular momentum

8. Bohr Model of Hydrogen
Electron of the hydrogen atom can only be in specific energy states. p+
n=3
n=1
n=2 g
-13.6 eV
-3.4 eV
-1.5 eV
0 eV
Energy
Free e-

9. Matter Waves How can an electron go through two holes at once? g g g

10. Fundamental Paradox Wave/Particle Duality
Electron can be in multiple states at one time.
Godel’s Incompleteness Theorem
Can not have an all encompassing theory of everything.
Finiteness of man

11. End of Science? Positivism Limitation
Progress towards an ultimate understanding of the nature of reality.
Limitation
All universal models will be incomplete and possibly paradoxical.
Does not eliminate the usefulness of the model.

12. Wave Mechanics
DeBroglie Wavelength
Schrodinger’s Equation
Solution:

13. Quantum Numbers Principle QN Orbital QN Magnetic QN Spin n=1,2,3,…3d 4d 5d 6d 4f 5f
Principle QN
n=1,2,3,…
Orbital QN
l=0,1,2,…n-1
Magnetic QN
ml=-l,…0…+l
Spin
ms=-1/2,+1/2

14. Valence Electrons What states are filled by the electons of Ne? n = 4-1 1 -2 -1 1 2
n = 3 -1 1 -2 -1 1 2 ml
n = 2 -1 1 ml
n = 1 ml
l = 0
l = 1
l = 2

15. Lasers Light Amplification through Stimulated Emission of Radiation.
Ground State E1 E2
Metastable State E2 e- e- e- e- e- e- E1 E0