CHEM2524 Chemical Physics
From symmetry to surfaces, one lecture at a time.
- Exam
- 55% of the unit, in the exam period. The slides do not give its format, so check Canvas
- Online tests
- 2 tests, 5% each, weeks 5 and 11. 15 multiple-choice questions, one hour, one try
- Quizzes
- 10 weekly quizzes, 1% each, worst one dropped
- Formulas
- Every equation from the lectures, in one place. Open the formula sheet
423 quiz-style questions across the topics below. Each answer is explained.
Modules
Module 1: Symmetry
Why we use models, forces between particles, symmetry operations and point groups. Lectures 1 to 3.
Module 2: Crystals and diffraction
Lattices and unit cells, space groups, ionic crystal structures, Miller indices and Bragg diffraction, ionic radii and lattice energy. Lectures 4 to 7.
- Unit cells, crystal systems and Bravais lattices
- Crystal symmetry: glides, screws and space groups
- Reading a space group symbol
- Close packing and the holes between the atoms
- Ionic structures: rock salt, zinc blende, antifluorite, CsCl and rutile
- Measuring crystal structure: Miller indices and Bragg diffraction
- Ionic or covalent, ionic radii and radius ratios
- Lattice enthalpy: the Born–Mayer equation and its trends
Module 3: Solid-state materials
Bands, 1D, 2D and 3D conductors, semiconductors and superconductors, dielectrics and ferroelectrics, and magnetism. Lectures 8 to 11.
- Energy bands: how a pile of atoms becomes a metal, semiconductor or insulator
- Conductors in one, two and three dimensions
- Superconductivity, BCS theory and Mott-Hubbard localisation
- Bonding sets the bands: NaCl, SiC, TiS2 and ReO3
- Conductivity, carriers and how temperature changes them
- Doped semiconductors, p-n junctions and solar cells
- Dielectrics, capacitors and the structure of barium titanate
- Polarisation loops, lone pairs, piezoelectrics and second harmonic generation
- Magnetic moments, diamagnetism and paramagnetism
- Magnetic order: ferro-, antiferro- and ferrimagnets and the exchange that makes them
Module 4: Statistical mechanics
Microstates, configurations and weights, the Boltzmann distribution, temperature and the partition function. Lectures 12 and 13.
Module 5: Thermodynamics
Energy, entropy and free energy from the statistical view, open systems, ideal gases and solids. Lectures 14 to 17.
Module 6: Defects and phase transitions
Point defects in solids, interactions, mean-field theory and the thermodynamics of phase transitions. Lectures 18 to 22.
- Defects: why every real crystal has some, and how many
- Ionic conductivity: ions hop through gaps, and doping adds more gaps
- Phase transitions need interactions, and only sharpen with many particles
- Simulations: Monte Carlo, molecular dynamics and the Ising magnet
- Mean-field theory: replace the crowd with its average and a transition appears
- The van der Waals gas: two corrections to the ideal gas that predict liquids
- Chemical potential decides which phase wins, and phase diagrams map the winners
Module 7: Heat capacity, kinetics and glasses
Heat capacity and calorimetry, nucleation and the kinetics of phase transitions, glasses and metastable states. Lectures 23 to 25.
Module 8: Soft matter and liquids
Liquid crystals, Onsager theory, nematics in use, and diffusion as a random walk. Lectures 26 to 29.
- Soft matter and the kT yardstick
- Self-organisation and mesophases between liquid and crystal
- The order parameter and the hard-particle model of nematics
- Excluded volume, entropy and Onsager theory of the nematic
- Nematics in use: polarised light, electric fields and displays
- Random walks and diffusion: Fick's two laws
Module 9: Chemical kinetics
Rate laws, elementary steps and reaction mechanisms in the liquid phase. Lectures 30 and 31.
Module 10: Surfaces and interfaces
Surface tension, wetting, adhesion and friction, adsorption isotherms and the Gibbs adsorption isotherm. Lectures 32 to 36.
- Surfaces cost energy: surface tension, work of cohesion and why drops are round
- Wetting: spreading, contact angle, Young's equation and measuring surface tension
- Friction and adhesion: why surfaces grip and how glues hold
- Adsorption onto solids: physisorption, chemisorption, thin films and self-assembled monolayers
- Langmuir and BET isotherms: how much gas a surface holds, and how big the surface is
- The Gibbs adsorption isotherm: surface excess, surfactants and the cmc
Module 11: Metal-organic frameworks
Building MOFs from nodes and linkers, porosity, and what their structure makes them good for. Lectures 37 to 39.
- Building MOFs: nodes, linkers and crystal engineering
- Thermal expansion and why cyanide frameworks can shrink when heated
- Tuning NTE: how the metal ion and crystal field stabilisation set bond strength
- MOFs as sponges for gas: hydrogen, carbon dioxide and methane
- MOFs that act as magnets, wires, proton conductors and spin switches
Module 12: Practice exam questions
The practice exam questions shown at the end of Lecture 39, covering Lectures 6 to 11 and 37 to 38, worked through step by step.