Grimme D3 dispersion

Classes
struct	excgrid::D3Parameters
struct	excgrid::D3Result

Functions
Result< D3Parameters >	excgrid::D3Preset (std::string_view name)
Result< double >	excgrid::GrimmeD3Energy (const Geometry &geometry, const D3Parameters &parameters)
Result< D3Result >	excgrid::GrimmeD3 (const Geometry &geometry, const D3Parameters &parameters)

Variables
double	excgrid::D3Parameters::s6 = 1.0
	Global C6 scale.
double	excgrid::D3Parameters::s8 = 1.0
	C8 scale.
double	excgrid::D3Parameters::rs6 = 1.0
	The a1 damping scale of the R^6 term.
double	excgrid::D3Parameters::alpha6 = 14.0
	The a2 exponent of the R^6 term.
double	excgrid::D3Parameters::rs8 = 1.0
	The a1 damping scale of the R^8 term.
double	excgrid::D3Parameters::alpha8 = 16.0
	The a2 exponent of the R^8 term (alpha6 + 2).
double	excgrid::D3Result::energy = 0.0
	The dispersion energy (Hartree).
std::vector< std::array< double, 3 > >	excgrid::D3Result::gradient
	One 3-vector per atom (Hartree/Bohr).

Detailed Description

The DFT-D3 two-body dispersion correction (Grimme, Antony, Ehrlich, Krieg, J. Chem. Phys. 132 (2010) 154104), zero-damping scheme: geometry-only closed forms - energy plus analytic coordinate gradients, hand-written (no codegen), over the library's own Geometry type. Coordination-number-dependent C6 interpolation, the C8 estimate, and the counting-function coordination numbers follow the published scheme; the parameter data is committed under tools/data/ (see tools/gen_d3_tables.py).

Function Documentation

D3Preset()

Result< D3Parameters > excgrid::D3Preset

(

std::string_view

name

)

The standard D3 zero-damping parameter set of one method family (transcribed from the published D3 parameter data).

Parameters

name	One of "b3lyp", "pbe", "pbe0", "bp86" (the b-p set), "blyp", "revpbe", "pbesol", "b97d", "tpss", "bpbe", "bhandhlyp", "b3pw91", "hf".

Returns

The parameter set, or kInvalidArgument for an unknown name.

GrimmeD3()

Result< D3Result > excgrid::GrimmeD3	(	const Geometry &	geometry,
		const D3Parameters &	parameters )

The D3 energy and its analytic coordinate gradient in one pass.

Parameters

geometry	The molecule.
parameters	The functional's parameter set.

Returns

The energy and the gradient, or kUnsupported for an out-of-table element.

GrimmeD3Energy()

Result< double > excgrid::GrimmeD3Energy	(	const Geometry &	geometry,
		const D3Parameters &	parameters )

The D3 dispersion energy of the geometry, in Hartree.

Parameters

geometry	The molecule.
parameters	The functional's parameter set.

Returns

The energy (negative, attractive), or kUnsupported for an element above the table's range.