Hartee Fock Theory
Hartree–Fock theory approximates the many-electron wavefunction using this mathematical object.
slater determinant
Basis sets are mathematical functions used to approximate this
AO/MO
These orbitals decay exponentially and resemble real atomic orbitals more closely
STO
This approximation assumes nuclei remain fixed while electrons move.
Born-Oppenheimer approximation
This theorem states electrons occupy the lowest-energy orbitals first.
aufbau principle
This principle ensures the Hartree–Fock wavefunction changes sign when two electrons are exchanged.
pauli exclusion principle
This basis set notation indicates split-valence with polarization and diffuse functions: 6-311++G(3df,2pd).
pople style basis set
These orbitals are computationally easier because Gaussian integrals are simpler.
GTOs
The variational principle states the approximate energy can never be this relative to the true ground-state energy.
lower
This method allows different spatial orbitals for alpha and beta electrons.
unrestricted Hartee fock
Hartree–Fock theory neglects this important interaction effect between electron motions.
electron correlation
Diffuse functions are especially important for describing these types of species.
excited state
GTOs differ from STOs because they decay according to this mathematical form.
Gaussian decay/exponentinal squared decay
This computational philosophy improves Hartree–Fock by including electron correlation directly.
post Hartee fock methods
Small-core ECPs simplify calculations by replacing these electrons.
core electrons
The “SCF” procedure in Hartree–Fock stands for this.
self-consistent field
Polarization functions allow orbitals to do this.
change shape during bonding
Contracted Gaussian functions were developed to make GTOs behave more like these orbitals.
STOs
Density Functional Theory primarily uses this quantity instead of the full wavefunction.
electron density
The overlap integral measures this between orbitals.
orbital overlap
The Hartree–Fock limit refers to the energy obtained with this condition.
infinitely complete basis set
Split-valence basis sets improve calculations because valence electrons are treated with this increased flexibility.
multiple basis function per valence orbital
One disadvantage of STOs is this computational issue.
high computational cost
The direct SCF method improves efficiency by reducing storage of these quantities.
2 electron integrals
Hartree products fail because they do not properly account for this electron property.
antisymmetry