VOLT
Plugins

Wigner-Seitz Defect Analysis

Identify vacancies, interstitials and antisites by comparing the current configuration against a reference lattice using Wigner-Seitz cells.

Parameters

ParameterTypeDefaultDescription
referenceframeReference frame defining the lattice sites. Required; its atom count generally differs from the current frame, which is how vacancies and interstitials are detected.
affineMappingselectoffAffine mapping applied before site assignment. Options: off, toReference (map to reference cell), toCurrent (map to current cell).
eliminateCellDeformationbooleanfalseEliminate cell deformation before site assignment.
minimumImageConventionbooleantrueUse the minimum image convention for site assignment.

Output

The plugin writes two parquet files per frame.

{outputBase}_wigner_seitz.parquet

Per-site summary for the frame. main_listing holds the defect tallies; per-site-properties lists every reference site with its occupancy.

interface WignerSeitzSite {
    site_index: int;
    site_id: int;
    pos: [float, float, float];
    occupancy: int;
}

interface WignerSeitzOutput {
    main_listing: {
        vacancy_count: int;
        interstitial_count: int;
        antisite_count: int;
        occupied_count: int;
        total_sites: int;
        total_current_atoms: int;
    };
    "per-site-properties": WignerSeitzSite[];
}

{outputBase}_atoms.parquet

Per-atom data in AtomisticExporter format, consumed by the VOLT viewer for 3D rendering. The rows are a synthetic frame built from the reference sites (plus one extra record per excess occupant), so vacancies — which have no current atom — are still rendered. Atoms are bucketed by defect role under group names Vacancy, Occupied, Antisite, and Interstitial. Each atom entry includes the standard atomistic fields plus:

interface WignerSeitzAtomFields {
    occupancy: int;
}

Surfaced in VOLT as the Wigner-Seitz Model exposure and exported as a .glb scene.

See Also

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