---
_id: '13118'
abstract:
- lang: eng
  text: Under high pressures and temperatures, molecular systems with substantial
    polarization charges, such as ammonia and water, are predicted to form superionic
    phases and dense fluid states with dissociating molecules and high electrical
    conductivity. This behaviour potentially plays a role in explaining the origin
    of the multipolar magnetic fields of Uranus and Neptune, whose mantles are thought
    to result from a mixture of H2O, NH3 and CH4 ices. Determining the stability domain,
    melting curve and electrical conductivity of these superionic phases is therefore
    crucial for modelling planetary interiors and dynamos. Here we report the melting
    curve of superionic ammonia up to 300 GPa from laser-driven shock compression
    of pre-compressed samples and atomistic calculations. We show that ammonia melts
    at lower temperatures than water above 100 GPa and that fluid ammonia’s electrical
    conductivity exceeds that of water at conditions predicted by hot, super-adiabatic
    models for Uranus and Neptune, and enhances the conductivity in their fluid water-rich
    dynamo layers.
acknowledgement: We acknowledge the crucial contribution of the LULI2000 laser and
  support teams to the success of the experiments. We also thank S. Brygoo and P.
  Loubeyre for useful discussions. This research was supported by the French National
  Research Agency (ANR) through the projects POMPEI (grant no. ANR-16-CE31-0008) and
  SUPER-ICES (grant ANR-15-CE30-008-01), and by the PLAS@PAR Federation. M.F. and
  R.R. gratefully acknowledge support by the DFG within the Research Unit FOR 2440.
  M.B. was supported by the European Union within the Marie Skłodowska-Curie actions
  (xICE grant 894725) and the NOMIS foundation. The DFT-MD calculations were performed
  at the North-German Supercomputing Alliance facilities.
article_processing_charge: No
article_type: original
author:
- first_name: J.-A.
  full_name: Hernandez, J.-A.
  last_name: Hernandez
- first_name: Mandy
  full_name: Bethkenhagen, Mandy
  id: 201939f4-803f-11ed-ab7e-d8da4bd1517f
  last_name: Bethkenhagen
  orcid: 0000-0002-1838-2129
- first_name: S.
  full_name: Ninet, S.
  last_name: Ninet
- first_name: M.
  full_name: French, M.
  last_name: French
- first_name: A.
  full_name: Benuzzi-Mounaix, A.
  last_name: Benuzzi-Mounaix
- first_name: F.
  full_name: Datchi, F.
  last_name: Datchi
- first_name: M.
  full_name: Guarguaglini, M.
  last_name: Guarguaglini
- first_name: F.
  full_name: Lefevre, F.
  last_name: Lefevre
- first_name: F.
  full_name: Occelli, F.
  last_name: Occelli
- first_name: R.
  full_name: Redmer, R.
  last_name: Redmer
- first_name: T.
  full_name: Vinci, T.
  last_name: Vinci
- first_name: A.
  full_name: Ravasio, A.
  last_name: Ravasio
citation:
  ama: Hernandez J-A, Bethkenhagen M, Ninet S, et al. Melting curve of superionic
    ammonia at planetary interior conditions. <i>Nature Physics</i>. 2023;19:1280-1285.
    doi:<a href="https://doi.org/10.1038/s41567-023-02074-8">10.1038/s41567-023-02074-8</a>
  apa: Hernandez, J.-A., Bethkenhagen, M., Ninet, S., French, M., Benuzzi-Mounaix,
    A., Datchi, F., … Ravasio, A. (2023). Melting curve of superionic ammonia at planetary
    interior conditions. <i>Nature Physics</i>. Springer Nature. <a href="https://doi.org/10.1038/s41567-023-02074-8">https://doi.org/10.1038/s41567-023-02074-8</a>
  chicago: Hernandez, J.-A., Mandy Bethkenhagen, S. Ninet, M. French, A. Benuzzi-Mounaix,
    F. Datchi, M. Guarguaglini, et al. “Melting Curve of Superionic Ammonia at Planetary
    Interior Conditions.” <i>Nature Physics</i>. Springer Nature, 2023. <a href="https://doi.org/10.1038/s41567-023-02074-8">https://doi.org/10.1038/s41567-023-02074-8</a>.
  ieee: J.-A. Hernandez <i>et al.</i>, “Melting curve of superionic ammonia at planetary
    interior conditions,” <i>Nature Physics</i>, vol. 19. Springer Nature, pp. 1280–1285,
    2023.
  ista: Hernandez J-A, Bethkenhagen M, Ninet S, French M, Benuzzi-Mounaix A, Datchi
    F, Guarguaglini M, Lefevre F, Occelli F, Redmer R, Vinci T, Ravasio A. 2023. Melting
    curve of superionic ammonia at planetary interior conditions. Nature Physics.
    19, 1280–1285.
  mla: Hernandez, J. A., et al. “Melting Curve of Superionic Ammonia at Planetary
    Interior Conditions.” <i>Nature Physics</i>, vol. 19, Springer Nature, 2023, pp.
    1280–85, doi:<a href="https://doi.org/10.1038/s41567-023-02074-8">10.1038/s41567-023-02074-8</a>.
  short: J.-A. Hernandez, M. Bethkenhagen, S. Ninet, M. French, A. Benuzzi-Mounaix,
    F. Datchi, M. Guarguaglini, F. Lefevre, F. Occelli, R. Redmer, T. Vinci, A. Ravasio,
    Nature Physics 19 (2023) 1280–1285.
date_created: 2023-06-04T22:01:02Z
date_published: 2023-09-01T00:00:00Z
date_updated: 2024-08-20T05:59:32Z
day: '01'
department:
- _id: BiCh
doi: 10.1038/s41567-023-02074-8
external_id:
  isi:
  - '000996921200001'
intvolume: '        19'
isi: 1
language:
- iso: eng
month: '09'
oa_version: None
page: 1280-1285
publication: Nature Physics
publication_identifier:
  eissn:
  - 1745-2481
  issn:
  - 1745-2473
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
  link:
  - relation: erratum
    url: https://doi.org/10.1038/s41567-023-02130-3
scopus_import: '1'
status: public
title: Melting curve of superionic ammonia at planetary interior conditions
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 19
year: '2023'
...