qml.qchem.core_matrix

core_matrix(basis_functions, charges, r)

Return a function that computes the core matrix for a given set of basis functions.

The core matrix is computed as a sum of the kinetic and electron-nuclear attraction matrices.

Parameters

• basis_functions (list[BasisFunction]) – basis functions

• charges (list[int]) – nuclear charges

• r (array[float]) – nuclear positions

Returns

function that computes the core matrix

Return type

function

Example

>>> symbols  = ['H', 'H']
>>> geometry = np.array([[0.0, 0.0, 0.0], [0.0, 0.0, 1.0]], requires_grad = False)
>>> alpha = np.array([[3.42525091, 0.62391373, 0.1688554],
>>>                   [3.42525091, 0.62391373, 0.1688554]], requires_grad=True)
>>> mol = qml.qchem.Molecule(symbols, geometry, alpha=alpha)
>>> args = [alpha]
>>> core_matrix(mol.basis_set, mol.nuclear_charges, mol.coordinates)(*args)
array([[-1.27848869, -1.21916299], [-1.21916299, -1.27848869]])

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