Modern Physics Teaching

Modern Physics

Instructor: Dr. [Sabieh Anwar] Office hours: Monday, (2-6 pm); Friday, (3-5 pm)

Teaching Fellows: [Shahid Sattar] Office hours: Wednesday(12-3 pm), Thursday(12-3 pm) and [Shama Rashid] Office hours: Monday, Tuesday and Thursday (3-5 pm)

Textbook: Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles by R. Eisberg and R. Resnick. (The book is available in the library for Rs. 1100.)

Week 1

• Blackbody radiation
• Spectral radiance (experimental results); Stefan's and Wien's displacement law
• Density of modes and average energies using principle of equipartition of energy
• Rayleigh-Jeans formula
• Planck's correction
• Energy is quantized!

Week 2

• Particle nature of electromagnetic radiation
• The photoelectric effect
• Compton Scattering
• What are X-rays?
• Pair production and Pair annihilation
• Light:particles or waves?

Week 3

• Wave-particle duality and de Broglie relationship
• Electron diffraction and interference (some original experiments)
• Matter waves and wave packets
• Relationship between position and momentum spaces and origins of Uncertainty principle

Week 4

• Uncertainty principle (position and momentum; energy and time)
• Atomic spectroscopy and lifetime broadening
• Bohr's model
• The concept of reduced mass
• Sommerfeld and Wilson's quantization

Weeks 5 and 6

• Motivation for the Schrodinger Equation
• Wavefunction and its probabilistic interpretation
• Expectation values, legitimate definition
• Corresponding principle
• Time independent Schrodinger Equation
• Solving the Schrodinger Equation for a free particle

Week 7

• Acceptable solutions of the Schrodinger Equation; legitimate wavefunctions
• Particle in an infinite well

Week 8 (This weak is devoted to revisions and addressing misconceptions)

• How do electrons get across nodes? Explanation This is not an easy question to answer. The simplest answer to the question is to stop thinking of the electron as a classical point particle behaving like a sphere. Rather, the best and the only way to describe the electron is through its wavefunction spread out in space. Then everything follows from there. I will discuss this further in the class.

Weeks 9 and 10

scanning tunneling microscope image of 5 nm gold nanoparticles (photograph by Dhirani)

STM of a silicon surface, showing individual silicon atoms (photograph by IBM)

• Particle in a finite well (do-it-yourself)
• Step potential when energy is less than the potential height
• Step potential when energy is greater than the potential height
• Barrier potential, quantum mechanical tunneling, reflectivity and transmittivity
• Ramseur effect, size resonance
• Analogies with optics:
  • reflectivity from a dielectric
  • total internal reflection and evanescent waves
  • frustrated total internal reflection
• Scanning tunneling microscopy
• Schottky barrier
• Field emission: metal placed in an electric field

Week 11

• The H atom
• Solving the three dimensional Schrodinger equation for a spherical potential
• Origin of principal, azimuthal and orbital quantum numbers
• orbitals: s, p, d and f
• full derivation of spherical harmonic functions as solutions of the polar part of Schrodinger's equation

3D H atom orbital viewer

Weeks 12 and 13

• Orbitals continued
• Degeneracy and symmetry considerations for the free H atom
• Radial wavefunction
• radial probability density

Week 14

• angular momentum in quantum mechanics
• space quantization
• significance of the quantum numbers, n, l and m_l