quemb.kbe.fragment.fragmentate

quemb.kbe.fragment.fragmentate(mol, kpt, *, natom=0, frag_type='autogen', unitcell=1, iao_valence_basis=None, n_BE=2, frozen_core=False, self_match=False, allcen=True, print_frags=True, additional_args=None)

Fragment/partitioning definition

Interfaces the main fragmentation function (autogen) in MolBE. It defines edge & center for density matching and energy estimation. It also forms the base for IAO/PAO partitioning for a large basis set bootstrap calculation. Fragments are constructed based on atoms within a unitcell.

Parameters:

  • frag_type (Literal['autogen']) – Name of fragmentation function. ‘autogen’ and ‘chemgen’ are supported. Defaults to ‘autogen’

  • n_BE (int) – Specifies the order of bootstrap calculation in the atom-based fragmentation, i.e. BE(n). For a simple linear system A-B-C-D, BE(1) only has fragments [A], [B], [C], [D] BE(2) has [A, B, C], [B, C, D]

  • mol (Cell) – pyscf.pbc.gto.cell.Cell object. This is required for the options, ‘autogen’, and ‘chain’ as frag_type.

  • iao_valence_basis (str | None) – Name of minimal basis set for IAO scheme. ‘sto-3g’ suffice for most cases.

  • frozen_core (bool) – Whether to invoke frozen core approximation. This is set to False by default

  • print_frags (bool) – Whether to print out list of resulting fragments. True by default

  • kpt (list[int] | tuple[int, int, int]) – No. of k-points in each lattice vector direction. This is the same as kmesh.

  • additional_args (ChemGenArgs | AutogenArgs | None) – Additional arguments for different fragmentation functions.

Return type:

FragPart