Diamond (nanocrystalline)

Pure sp³ endpoint: every Voronoi grain is cut from the cubic diamond reference (Fd-3m, a = 3.561 Å). Randomly rotated tetrahedral networks meet at grain boundaries, giving a nanocrystalline diamond panel, the cleanest tetrahedral g3 signature on the regime ladder.

Parameters

cell.generate(
    shell_target,
    num_steps=150,
    grain_size=14.0,
    grain_sources=[
        {"atoms": atoms_graphite, "species_offset": 0, "weight": 0.00},
        {"atoms": atoms_diamond,  "species_offset": 1, "weight": 1.00},
    ],
    bond_weight=2.5, angle_weight=1.2, repulsion_weight=2.0,
    hard_core_scale=0.92, nonbond_push_scale=0.85,
    displacement_sigma=0.02,
)

Relaxation trajectory

Navy tetrahedra decorate every C atom whose four neighbours form a 109.5° tetrahedron; no triangles because no atoms were flagged as sp² during grain construction.

g3 distribution