7. API

7.1. chilli_py

This is a pure Python self-consistent field code utilizing

Gaussian-type orbitals (GTOs).

Thus you will find only source code written

in this package in Python and no other language.

by Sebastian Schwalbe and Kai Trepte

7.2. How to use

>>> from chilli_py import simple_run
>>> simple_run.run("H2","RHF")

class chilli_py.Atoms(sym, pos, spin=0, charge=0)

Atoms class Contains variables describing the system.

Input

• sym: list(str), chemical symbols

• pos: list(list(3,), positions

• spin: int(), spin of the system

• charge: int(), charge of the system

show()

Show the representation of a class instance.

class chilli_py.BasisSet

BasisSet class Construct for atoms object the CGBF basis.

add(bf)

Add new basis function (bf) to basis. For Gaussians bf is a CGBF.

static initialize(atoms, basis_name='sto-3g')

Initialize a BasisSet instance from a basis name.

Input

• atoms: Atoms(), chilli_pys Atoms object

• basis_name: str(), basis set name, e.g., “sto-3g”

show()

Show the representation of the instance.

class chilli_py.Grids(atoms, n_rad, n_ang, **kwargs)

Grids class Produce a real-space grid (optimal) for Gaussian integrals.

Input

• atoms: Atoms()

• n_rad: int()

• n_ang: int()

eval(basis)

Evaluate basis on grid.

get_grad(D)

get_grid()

For all atoms in the system a atomic grid is produced and combined to a system grid (real-space grid).

get_rho(D)

Get rho(r) from density matrix D using the basis evaluated on the grid basis_ongrid.

get_sigma(grad)

grad(basis)

class chilli_py.RHF(atoms, basis_name='sto-3g', **kwargs)

RHF class Restricted Hartree-Fock (RHF) class.

Input

• atoms

• basis

class chilli_py.RKS(atoms, basis_name='sto-3g', grids=(100, 110), **kwargs)

RKS class Restricted Kohn-Sham (RKS). Performs a RKS calculation.

Input

• atoms: Atoms()

• basis_name: str(), basis set name

• grids: tuple(), e.g., (100,110)

kernel()

Kernel function executing the self-consistent field calculation.