{
  "abstract": "Multiphonon relaxation decides whether a lanthanide ion emits light or heats its host. Since 1968 it has been predicted from the host’s maximum phonon energy, although the excitation resides on a single ion. First-principles force constants and five decades of relaxation measurements show that the accepting vibration is the stretch of the dopant’s coordination cage, a site property set by local chemistry. Aliovalent substitution stiffens the cage by up to 27%, and across seven halide hosts the cage frequency departs from the host frequency by −21% to +19%. It predicts measured effective phonon frequencies three times more accurately than the host frequency, and in its quanta the seven energy-gap laws share one room-temperature slope. The site-resolved laws map the lattice limits of optical refrigeration from 2 to 6 µm. The phonon count of a lanthanide emitter becomes a site property that chemistry can tune and theory can compute before synthesis.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry",
    "The University of Chicago"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Daqian Bian",
      "orcid": "0000-0002-8774-3733"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3yepdr9nb7hjz.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15010222/v1",
  "fulltext_url": null,
  "id": "3yepdr9nb7hjz",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010222/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2505|Luminescence Properties of Advanced Materials"
    ]
  ],
  "openalex": "W7221541628",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15010222/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-11",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/3yepdr9nb7hjz.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:22Z",
      "native_id": "10.26434/chemrxiv.15010222",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010222/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Luminescence Properties of Advanced Materials",
      "subfield": "materials-polymers"
    }
  ],
  "title": "The Dopant Cage Sets the Phonon Count of Lanthanide Emitters",
  "title_text": "The Dopant Cage Sets the Phonon Count of Lanthanide Emitters",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:22Z",
  "url": "https://research.draconitic.com/paper/3yepdr9nb7hjz",
  "venue": "ChemRxiv",
  "versions": []
}