Hartree-Fock and What a Basis Set Decides · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Solving for electrons, one field at a time

Science · Chemistry · ages 20-21
Name ______________________   Date ____________

  1. What does convergence of the cycle mean?

    • The computer overheats
    • The answer stops changing
    • The molecule falls apart

  2. What field does each electron move in during Hartree-Fock?

    • The average field of the other electrons
    • A magnetic field from the lab
    • No field at all

  3. What is the missing energy called?

    • Kinetic energy
    • Correlation energy
    • Solar energy

  4. An anion energy comes out far too high with a compact basis. What is the fix?

    • Remove all functions
    • Freeze the geometry
    • Add diffuse functions

  5. What does a polarised basis set add over split-valence?

    • Lopsided shapes that describe bonding
    • Heavier nuclei
    • More electrons

  6. A minimal basis set describes bonding as well as a polarised one.

    Circle one:   True   False

  7. Running more SCF cycles after convergence improves the energy.

    Circle one:   True   False

  8. Two calculations on one anion differ only in basis set, and one energy is much lower. Which is more reliable?

    • The higher one, higher means better
    • Neither, anions forbid calculation
    • The lower one with diffuse functions, it can hold the extra electron
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Solving for electrons, one field at a time W1-mt_EYSTCPuRNx-s1

  1. The answer stops changing · Stable answers across cycles mean the field agrees with its orbitals.
  2. The average field of the other electrons · Each electron sees the mean field, not each peer instantly.
  3. Correlation energy · Instant avoidance of electrons is absent from the mean field.
  4. Add diffuse functions · Diffuse shapes reach far out where the extra electron lives.
  5. Lopsided shapes that describe bonding · Extra shapes let orbitals bend into bonds.
  6. False · Minimal sets lack the shapes that bending bonds need.
  7. False · Converged means stable, so extra cycles change nothing.
  8. The lower one with diffuse functions, it can hold the extra electron · The set that reaches the outer electron describes the anion better.
Worksheet · LightMySky