occ::qm::guess Namespace Reference

Classes
struct	SubshellOccupation
	One subshell of a neutral atom's minimal-basis configuration. More...

Functions
std::vector< SubshellOccupation >	minimal_basis_subshell_occupations (int Z)
	A neutral atom's minimal-basis configuration, in filling order.
int	ground_state_multiplicity (int Z)
	Spin multiplicity 2S+1 of the neutral atom's ground state, for Z in 1..118; 0 for anything outside that range.
Mat	compute_sap_matrix (const std::vector< occ::core::Atom > &atoms, const AOBasis &basis)
	Superposition of atomic potentials, as a one-electron matrix in basis.

Function Documentation

compute_sap_matrix()

Mat occ::qm::guess::compute_sap_matrix	(	const std::vector< occ::core::Atom > &	atoms,
		const AOBasis &	basis
	)

Superposition of atomic potentials, as a one-electron matrix in basis.

Uses whichever fit AOBasis::load_sap_basis provides; there is no choice to make here, and the parameter this once took named a basis it did not actually load.

ground_state_multiplicity()

int occ::qm::guess::ground_state_multiplicity

(

int

Z

)

Spin multiplicity 2S+1 of the neutral atom's ground state, for Z in 1..118; 0 for anything outside that range.

These are the experimental ground-state terms, so they include the cases Hund's rule alone gets wrong – chromium and copper take an electron from the s shell to half-fill or fill the d shell, palladium empties its s shell entirely. An effective core potential removes only closed shells, so the same multiplicity applies to the valence-only atom: gold keeps its one unpaired 6s electron whether or not its core is replaced.

minimal_basis_subshell_occupations()

std::vector< SubshellOccupation > occ::qm::guess::minimal_basis_subshell_occupations

(

int

Z

)

A neutral atom's minimal-basis configuration, in filling order.

Labelled by (n, l) rather than left as a flat vector, because the minimal basis does not list its shells in filling order: STO-3G gives iron 1s 2s 2p 3s 3p 4s 4p 3d, with the d shell last. Anything that places these occupations has to match them up by subshell, not by position.