{
  "annotation_id": "9c932159-f4b1-417f-a41a-1f44f72d7421",
  "date_created": "2026-03-02T18:01:46.138000Z",
  "date_modified": "2026-03-02T18:01:46.138000Z",
  "file_hash": "b0c3eeb36b9ea4b6210edfe1468b322b35d19111e8d0d1ae50b4b1623003de72",
  "private": false,
  "record": {
    "abstract": "We consider double ionization of atoms or ions by electron impact in the\npresence of a static electric field. As in Wanniers analysis of the analogous\nsituation without external field the dynamics near threshold is dominated by a\nsaddle. With a field the saddle lies in a subspace of symmetrically escaping\nelectrons. Near threshold the classical cross section scales with excess energy\nE like sigma=E^alpha, where the exponent alpha can be determined from the\nstability of the saddle and does not depend on the field strength. For example,\nif the remaining ion has charge Z=2, the exponent is 1.292, significantly\ndifferent from the 1.056 without the field.",
    "arxiv_id": "quant-ph/0109143",
    "authors": [
      "Bruno Eckhardt",
      "Krzysztof Sacha"
    ],
    "categories": [
      "quant-ph",
      "nlin.CD",
      "physics.atom-ph"
    ],
    "doi": "10.1209/epl/i2001-00570-7",
    "journal_ref": "Europhysics Letters 56, 651 (2001).",
    "title": "Wannier threshold law for two electron escape in the presence of an   external electric field",
    "url": "https://arxiv.org/abs/quant-ph/0109143"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "9e8d3f45-d1cf-4f56-9b60-0eda301739ba",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}