AtomsBuilder

Helper function to convert construct a FlexibleSystem from a list of positions, elements, cell matrix and pbc tuple

bulk(sym) : generates a FlexibleSystem unit cell for a bulk crystal structure. If sym is a chemical symbol then the phase and lattice constant are taken from a database that is consistent with ASE. If sym is one of [:fcc, :bcc, :diamond, :hcp] then one needs to specify the kwargs a or c to determine the lattice constants.

randz!(sys::FlexibleSystem, zlist) -> sys

Randomly assigns elements to the atoms in the system sys according to the probabilities given in zlist. zlist is an iterable over pairs of the form id => p where id is an atom id (e.g. atomic number or chemical symbol) and p a probability. E.g.,

sys = bulk(:Ti, cubic=true) * 3
sys = randz!(sys, [ :Ti => 0.2, :O => 0.8 ])

This function was developed mostly for generating testing systems. It may not be suitable for generating random alloys. PRs to improve it are welcome.

rattle!(sys, r::Union{AbstractFloat, Quantity}) -> at

Randomly perturbs the atom positions within a ball of radius r. The perturbation is uniform in angular component, and uniform in radial component. (Note this is not the same as choosing them uniform in cartesian coordinates!).

If r is unitless, then the unit of the system is applied.

union(sys1::FlexibleSystem, sys2::FlexibleSystem)

takes the union of two particle systems provided their cells are identical.

deleteat!(sys::FlexibleSystem, n) -> sys:

returns the same FlexibleSystemobjectsys, but with the atom(s) specified byn` removed.

repeat(at, n::NTuple{3})
repeat(at, n::Integer)

Takes a structure and repeats it n_j times into the j-th cell-vector direction. For example,

at = repeat(bulk(:C), (3,2,4))

creates 3 x 2 x 4 unit cells of carbon.

The same can be achieved by *:

at = bulk(:) * (3, 2, 4)