Quantum Chemistry IV — The Machinery
Courses
Everything between a minimal-basis toy and a production code: integral recurrences past s-type (McMurchie-Davidson, Obara-Saika), SCF convergence technology, analytic gradients, optimization on potential energy surfaces, and response properties — with live wasm demonstrations compiled from the Knot DSL.
Quantum Chemistry IV — The MachineryCourse cleared — every checkpoint passed 🎉0/0 units cleared · 0/0 questions · 20 planned · ~9h
Integrals past s-type
plannedAngular momentum enters: Hermite Gaussians and the recurrences production codes run.
- lessonHermite Gaussians and the McMurchie-Davidson ideaplanned
- readingReading — McMurchie-Davidsonplanned
- readingReading — Obara-Saikaplanned
- exercisesExercises — Run the recurrences by hand for p-functionsplanned
- projectProject — p-orbital overlap & kinetic via MD recurrenceplanned
- Live — Water in 6-31G(d), compiled from Knot to wasmplanned
SCF technology
plannedDIIS, damping, level shifts, guesses — convergence as an engineering discipline.
- lessonDIIS: extrapolating in error spaceplanned
- projectProject — Add DIIS to your SCF; count the iterations it savesplanned
- lessonConvergence pathologies and the fixes that actually workplanned
Gradients
plannedHellmann-Feynman, Pulay forces, and why atom-centered bases make derivatives subtle.
- lessonHellmann-Feynman and its fine printplanned
- exercisesExercises — Derive the Pulay termsplanned
- projectProject — Analytic vs finite-difference gradient of E(R)planned
Geometry optimization
plannedNewton on the PES, internal coordinates, transition states.
- lessonWalking the surface: quasi-Newton and coordinates that helpplanned
- projectProject — Optimize the H₂ bond length with your own gradientplanned
- Live — Watch water relax (Knot → wasm)planned
Properties & response
plannedPolarizability, vibrational frequencies, and the road to spectra.
- projectProject — Polarizability by finite fieldplanned
- projectProject — Harmonic frequency of H₂ vs the experimental 4401 cm⁻¹planned
- lessonResponse theory in one lessonplanned
Symmetry
plannedPoint groups and how codes exploit them.
- lessonPoint groups for quantum chemistryplanned
- exercisesExercises — Symmetry-block a small Hamiltonianplanned