EmpiricalDispersion¶

class psi4.driver.EmpiricalDispersion(name_hint=None, level_hint=None, param_tweaks=None, **kwargs)[source]¶

Bases: object

Lightweight unification of empirical dispersion calculation modes.

dashlevel¶

Name of dispersion correction to be applied. Resolved from name_hint and/or level_hint into a key of dashparam.dashcoeff.

Type:	{‘d1’, ‘d2’, ‘d3zero’, ‘d3bj’, ‘d3mzero’, ‘d3mbj’, ‘chg’, ‘das2009’, ‘das2010’, ‘nl’}

dashparams¶

Complete (number and parameter names vary by dashlevel) set of parameter values defining the flexible parts of dashlevel. Resolved into a complete set (keys of dashcoeff[dashlevel][‘default’]) from name_hint and/or dashcoeff_supplement and/or user param_tweaks.

Type:	dict

fctldash¶

If dashparams for dashlevel corresponds to a defined, named, untweaked “functional-dashlevel” set, then that functional. Otherwise, empty string.

Type:	str

description¶

Tagline for dispersion dashlevel.

Type:	str

dashlevel_citation¶

Literature reference for dispersion dashlevel in general, not necessarily for dashparams.

Type:	str

dashparams_citation¶

Literature reference for dispersion parameters, if dashparams corresponds to a defined, named, untweaked “functional-dashlevel” set with a citation. Otherwise, empty string.

Type:	str

dashcoeff_supplement¶

See description in qcdb.intf_dftd3.dashparam.from_arrays. Used here to “bless” the dispersion definitions attached to the procedures/dft/*_functionals-defined dictionaries as legit, non-custom, and of equal validity to qcdb.intf_dftd3.dashparam.dashcoeff itself for purposes of validating fctldash.

Type:	dict

engine¶

Compute engine for dispersion. One of Psi4’s internal libdisp library, Grimme’s DFTD3 executable, or nl.

Type:	{‘libdisp’, ‘dftd3’, ‘nl’}

disp¶

Only present for engine=libdisp. Psi4 class instance prepared to compute dispersion.

Type:	psi4.core.Dispersion

ordered_params¶

Fixed-order list of relevant parameters for dashlevel. Matches DFT_DISPERSION_PARAMETERS ordering. Used for printing.

Type:	list

Parameters:

name_hint (str, optional) – Name of functional (func only, func & disp, or disp only) for which to compute dispersion (e.g., blyp, BLYP-D2, blyp-d3bj, blyp-d3(bj), hf+d). Any or all parameters initialized from dashcoeff[dashlevel][functional-without-dashlevel] or dashcoeff_supplement[dashlevel][functional-with-dashlevel] can be overwritten via `param_tweaks.
level_hint (str, optional) – Name of dispersion correction to be applied (e.g., d, D2, d3(bj), das2010). Must be key in dashcoeff or “alias” or “formal” to one.
param_tweaks (list or dict, optional) – Values for the same keys as dashcoeff[dashlevel][‘default’] (and same order if list) used to override any or all values initialized by name_hint. Extra parameters will error.
engine (str, optional) – Override which code computes dispersion. See above for allowed values. Really only relevant for -D2, which can be computed by libdisp or dftd3.

Methods Summary

`compute_energy`(molecule)	Compute dispersion energy based on engine, dispersion level, and parameters in self.
`compute_gradient`(molecule)	Compute dispersion gradient based on engine, dispersion level, and parameters in self.
`compute_hessian`(molecule)	Compute dispersion Hessian based on engine, dispersion level, and parameters in self.
`print_out`()	Format dispersion parameters of self for output file.

Methods Documentation

compute_energy(molecule)[source]¶

Compute dispersion energy based on engine, dispersion level, and parameters in self.

Parameters:	molecule (psi4.core.Molecule) – System for which to compute empirical dispersion correction.
Returns:	Dispersion energy [Eh].
Return type:	float

Notes

DISPERSION CORRECTION ENERGY: Disp always set. Overridden in SCF finalization, but that only changes for “-3C” methods.
self.fctldash + DISPERSION CORRECTION ENERGY: Set if fctldash nonempty.

compute_gradient(molecule)[source]¶

Compute dispersion gradient based on engine, dispersion level, and parameters in self.

Parameters:	molecule (psi4.core.Molecule) – System for which to compute empirical dispersion correction.
Returns:	(nat, 3) dispersion gradient [Eh/a0].
Return type:	psi4.core.Matrix

compute_hessian(molecule)[source]¶

Compute dispersion Hessian based on engine, dispersion level, and parameters in self. Uses finite difference, as no dispersion engine has analytic second derivatives.

Parameters:	molecule (psi4.core.Molecule) – System for which to compute empirical dispersion correction.
Returns:	(3nat, 3nat) dispersion Hessian [Eh/a0/a0].
Return type:	psi4.core.Matrix

print_out()[source]¶: Format dispersion parameters of self for output file.

compute_energy(molecule)[source]

Compute dispersion energy based on engine, dispersion level, and parameters in self.

Parameters:	molecule (psi4.core.Molecule) – System for which to compute empirical dispersion correction.
Returns:	Dispersion energy [Eh].
Return type:	float

Notes

DISPERSION CORRECTION ENERGY: Disp always set. Overridden in SCF finalization, but that only changes for “-3C” methods.
self.fctldash + DISPERSION CORRECTION ENERGY: Set if fctldash nonempty.

compute_gradient(molecule)[source]

Compute dispersion gradient based on engine, dispersion level, and parameters in self.

Parameters:	molecule (psi4.core.Molecule) – System for which to compute empirical dispersion correction.
Returns:	(nat, 3) dispersion gradient [Eh/a0].
Return type:	psi4.core.Matrix

compute_hessian(molecule)[source]

Compute dispersion Hessian based on engine, dispersion level, and parameters in self. Uses finite difference, as no dispersion engine has analytic second derivatives.

Parameters:	molecule (psi4.core.Molecule) – System for which to compute empirical dispersion correction.
Returns:	(3nat, 3nat) dispersion Hessian [Eh/a0/a0].
Return type:	psi4.core.Matrix

print_out()[source]: Format dispersion parameters of self for output file.