gaint.obara_saika.electron_repulsion module

class gaint.obara_saika.electron_repulsion.ElectronRepulsion

Bases: object

The Obara-Saika scheme for three-dimensional nuclear attraction integral over primitive Gaussian orbitals.

p

The total exponent.

Type:

float

mu

The reduced exponent.

Type:

float

P

The centre of charge coordinate.

Type:

List[float,float,float]

C

The coordinate of given nuclei.

Type:

List[float,float,float]

Kab

The pre-exponential factor.

Type:

float

__init__(self)

Initialize the instance.

Eri(N, pga, pgb, pgc, pgd)

Evaluates nuclear attraction integral over two primitive gaussian orbitals.

Parameters:

• N (int) – Order of the boys function F_{N}(x).

• pga (PrimitiveGaussian) – The primitive gaussian orbital.

• pgb (PrimitiveGaussian) – The primitive gaussian orbital.

• pgc (PrimitiveGaussian) – The primitive gaussian orbital.

• pgd (PrimitiveGaussian) – The primitive gaussian orbital.

Returns:

vlaue – Integral value.

Return type:

float

recursive(r, N, pga, pgb, pgc, pgd, pga_1, pga_2, pgb_1, pgc_1, pgd_1)

Run the recurrence.

Parameters:

• r (int) – Cartesian index 0, 1, 2.

• N (int) – Order of the boys function F_{N}(x).

• pga_1 (PrimitiveGaussian) – The primitive gaussian orbital.

• pgb (PrimitiveGaussian) – The primitive gaussian orbital.

• pga_2 (PrimitiveGaussian) – The primitive gaussian orbital.

• pgb_1 (PrimitiveGaussian) – The primitive gaussian orbital.

Returns:

result – Integral value.

Return type:

float

gaussian_factory(r, pga, pgb, pgc, pgd)

Generate all gaussian orbitals in the Obara-Saikai recurrence equation.

Parameters:

• r (int) – Cartesian index 0, 1, 2.

• N (int) – Order of the boys function F_{N}(x).

• pga (PrimitiveGaussian) – The primitive gaussian orbital.

• pgb (PrimitiveGaussian) – The primitive gaussian orbital.

Returns:

result – Tuple of 8 PrimitiveGaussian orbital instance.

Return type:

Tuple(pg, pg, pg, pg, pg, pg, pg, pg)