sp³-rich mixed

20% graphite grains, 80% diamond grains. Diamond tetrahedra dominate the structure; residual sp² atoms live at grain boundaries as small 2D patches embedded in a 3D tetrahedral network.

Parameters

cell.generate(
    shell_target,
    num_steps=150,
    grain_size=14.0,
    grain_sources=[
        {"atoms": atoms_graphite, "species_offset": 0, "weight": 0.20},
        {"atoms": atoms_diamond,  "species_offset": 1, "weight": 0.80},
    ],
    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

g3 distribution