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46 lines
1.4 KiB
ReStructuredText
46 lines
1.4 KiB
ReStructuredText
========
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ao_basis
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========
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This module describes the atomic orbitals basis set.
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An |AO| :math:`\chi` centered on nucleus A is represented as:
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.. math::
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\chi_i({\bf r}) = (x-X_A)^a (y-Y_A)^b (z-Z_A)^c \sum_k c_{ki} e^{-\gamma_{ki} |{\bf r} - {\bf R}_A|^2}
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The |AO| coefficients are normalized as:
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.. math::
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{\tilde c}_{ki} = \frac{c_{ki}}{ \int \left( (x-X_A)^a (y-Y_A)^b (z-Z_A)^c e^{-\gamma_{ki} |{\bf r} - {\bf R}_A|^2} \right)^2 dr}
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.. warning::
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`ao_coef` contains the |AO| coefficients given in input. These do not
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include the normalization constant of the |AO|. The `ao_coef_normalized`
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provider includes this normalization factor.
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The |AOs| are also sorted by increasing exponent to accelerate the calculation of
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the two electron integrals.
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Complex Gaussian-Type Orbitals (cGTOs)
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=====================================
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Complex Gaussian-Type Orbitals (cGTOs) are also supported:
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.. math::
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\chi_i(\mathbf{r}) = x^a y^b z^c \sum_k c_{ki} \left( e^{-\alpha_{ki} \mathbf{r}^2 - \imath \mathbf{k}_{ki} \cdot \mathbf{r} - \imath \phi_{ki}} + \text{C.C.} \right)
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where:
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- :math:`\alpha \in \mathbb{C}` and :math:`\Re(\alpha) > 0` (specified by ``ao_expo`` and ``ao_expo_im``),
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- :math:`\mathbf{k} = (k_x, k_y, k_z) \in \mathbb{R}^3` (specified by ``ao_expo_pw``),
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- :math:`\phi = \phi_x + \phi_y + \phi_z \in \mathbb{R}` (specified by ``ao_expo_phase``).
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