[{"page":"1280-1285","publication":"Nature Physics","status":"public","intvolume":"        19","type":"journal_article","day":"01","date_created":"2023-06-04T22:01:02Z","department":[{"_id":"BiCh"}],"language":[{"iso":"eng"}],"publisher":"Springer Nature","scopus_import":"1","date_published":"2023-09-01T00:00:00Z","article_type":"original","month":"09","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.","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","quality_controlled":"1","oa_version":"None","_id":"13118","publication_identifier":{"eissn":["1745-2481"],"issn":["1745-2473"]},"volume":19,"date_updated":"2023-11-14T12:58:31Z","article_processing_charge":"No","author":[{"full_name":"Hernandez, J.-A.","last_name":"Hernandez","first_name":"J.-A."},{"id":"201939f4-803f-11ed-ab7e-d8da4bd1517f","orcid":"0000-0002-1838-2129","last_name":"Bethkenhagen","full_name":"Bethkenhagen, Mandy","first_name":"Mandy"},{"last_name":"Ninet","full_name":"Ninet, S.","first_name":"S."},{"last_name":"French","full_name":"French, M.","first_name":"M."},{"full_name":"Benuzzi-Mounaix, A.","last_name":"Benuzzi-Mounaix","first_name":"A."},{"full_name":"Datchi, F.","last_name":"Datchi","first_name":"F."},{"first_name":"M.","last_name":"Guarguaglini","full_name":"Guarguaglini, M."},{"last_name":"Lefevre","full_name":"Lefevre, F.","first_name":"F."},{"first_name":"F.","last_name":"Occelli","full_name":"Occelli, F."},{"first_name":"R.","last_name":"Redmer","full_name":"Redmer, R."},{"first_name":"T.","last_name":"Vinci","full_name":"Vinci, T."},{"first_name":"A.","full_name":"Ravasio, A.","last_name":"Ravasio"}],"abstract":[{"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.","lang":"eng"}],"publication_status":"published","citation":{"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.","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>","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.","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>.","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>"},"related_material":{"link":[{"relation":"erratum","url":"10.1038/s41567-023-02130-3"}]},"isi":1,"external_id":{"isi":["000996921200001"]},"title":"Melting curve of superionic ammonia at planetary interior conditions","year":"2023","doi":"10.1038/s41567-023-02074-8"},{"citation":{"mla":"Schörner, Maximilian, et al. “X-Ray Thomson Scattering Spectra from Density Functional Theory Molecular Dynamics Simulations Based on a Modified Chihara Formula.” <i>Physical Review E</i>, vol. 107, no. 6, 065207, American Physical Society, 2023, doi:<a href=\"https://doi.org/10.1103/PhysRevE.107.065207\">10.1103/PhysRevE.107.065207</a>.","ama":"Schörner M, Bethkenhagen M, Döppner T, et al. X-ray Thomson scattering spectra from density functional theory molecular dynamics simulations based on a modified Chihara formula. <i>Physical Review E</i>. 2023;107(6). doi:<a href=\"https://doi.org/10.1103/PhysRevE.107.065207\">10.1103/PhysRevE.107.065207</a>","short":"M. Schörner, M. Bethkenhagen, T. Döppner, D. Kraus, L.B. Fletcher, S.H. Glenzer, R. Redmer, Physical Review E 107 (2023).","ista":"Schörner M, Bethkenhagen M, Döppner T, Kraus D, Fletcher LB, Glenzer SH, Redmer R. 2023. X-ray Thomson scattering spectra from density functional theory molecular dynamics simulations based on a modified Chihara formula. Physical Review E. 107(6), 065207.","apa":"Schörner, M., Bethkenhagen, M., Döppner, T., Kraus, D., Fletcher, L. B., Glenzer, S. H., &#38; Redmer, R. (2023). X-ray Thomson scattering spectra from density functional theory molecular dynamics simulations based on a modified Chihara formula. <i>Physical Review E</i>. American Physical Society. <a href=\"https://doi.org/10.1103/PhysRevE.107.065207\">https://doi.org/10.1103/PhysRevE.107.065207</a>","ieee":"M. Schörner <i>et al.</i>, “X-ray Thomson scattering spectra from density functional theory molecular dynamics simulations based on a modified Chihara formula,” <i>Physical Review E</i>, vol. 107, no. 6. American Physical Society, 2023.","chicago":"Schörner, Maximilian, Mandy Bethkenhagen, Tilo Döppner, Dominik Kraus, Luke B. Fletcher, Siegfried H. Glenzer, and Ronald Redmer. “X-Ray Thomson Scattering Spectra from Density Functional Theory Molecular Dynamics Simulations Based on a Modified Chihara Formula.” <i>Physical Review E</i>. American Physical Society, 2023. <a href=\"https://doi.org/10.1103/PhysRevE.107.065207\">https://doi.org/10.1103/PhysRevE.107.065207</a>."},"publication_status":"published","abstract":[{"text":"We study ab initio approaches for calculating x-ray Thomson scattering spectra from density functional theory molecular dynamics simulations based on a modified Chihara formula that expresses the inelastic contribution in terms of the dielectric function. We study the electronic dynamic structure factor computed from the Mermin dielectric function using an ab initio electron-ion collision frequency in comparison to computations using a linear-response time-dependent density functional theory (LR-TDDFT) framework for hydrogen and beryllium and investigate the dispersion of free-free and bound-free contributions to the scattering signal. A separate treatment of these contributions, where only the free-free part follows the Mermin dispersion, shows good agreement with LR-TDDFT results for ambient-density beryllium, but breaks down for highly compressed matter where the bound states become pressure ionized. LR-TDDFT is used to reanalyze x-ray Thomson scattering experiments on beryllium demonstrating strong deviations from the plasma conditions inferred with traditional analytic models at small scattering angles.","lang":"eng"}],"author":[{"full_name":"Schörner, Maximilian","last_name":"Schörner","first_name":"Maximilian"},{"id":"201939f4-803f-11ed-ab7e-d8da4bd1517f","orcid":"0000-0002-1838-2129","last_name":"Bethkenhagen","full_name":"Bethkenhagen, Mandy","first_name":"Mandy"},{"full_name":"Döppner, Tilo","last_name":"Döppner","first_name":"Tilo"},{"full_name":"Kraus, Dominik","last_name":"Kraus","first_name":"Dominik"},{"last_name":"Fletcher","full_name":"Fletcher, Luke B.","first_name":"Luke B."},{"full_name":"Glenzer, Siegfried H.","last_name":"Glenzer","first_name":"Siegfried H."},{"last_name":"Redmer","full_name":"Redmer, Ronald","first_name":"Ronald"}],"arxiv":1,"article_processing_charge":"No","volume":107,"date_updated":"2023-08-02T06:30:46Z","oa":1,"publication_identifier":{"eissn":["2470-0053"],"issn":["2470-0045"]},"_id":"13231","oa_version":"Preprint","quality_controlled":"1","acknowledgement":"We want to thank P. Sperling, B. Witte, M. French, G. Röpke, H. J. Lee and A. Cangi for many helpful discussions. M. S. and R. R. acknowledge support by the Deutsche Forschungsgemeinschaft (DFG) within the Research Unit FOR 2440. All simulations and analyses were performed at the North-German Supercomputing Alliance (HLRN) and the ITMZ of the University of Rostock. M. B. gratefully acknowledges support by the European Horizon 2020 programme within the Marie Sklodowska-Curie actions (xICE grant 894725) and the\r\nNOMIS foundation. The work of T. D. was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","doi":"10.1103/PhysRevE.107.065207","year":"2023","external_id":{"isi":["001020265000002"],"arxiv":["2301.01545"]},"title":"X-ray Thomson scattering spectra from density functional theory molecular dynamics simulations based on a modified Chihara formula","article_number":"065207","isi":1,"main_file_link":[{"open_access":"1","url":"https://doi.org/10.48550/arXiv.2301.01545"}],"day":"14","type":"journal_article","intvolume":"       107","status":"public","publication":"Physical Review E","issue":"6","month":"06","article_type":"original","date_published":"2023-06-14T00:00:00Z","scopus_import":"1","publisher":"American Physical Society","language":[{"iso":"eng"}],"department":[{"_id":"BiCh"}],"date_created":"2023-07-16T22:01:10Z"},{"external_id":{"isi":["000939678300002"],"pmid":["36843123"]},"title":"Thermodynamics of diamond formation from hydrocarbon mixtures in planets","year":"2023","doi":"10.1038/s41467-023-36841-1","ddc":["540"],"tmp":{"image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"isi":1,"article_number":"1104","abstract":[{"lang":"eng","text":"Hydrocarbon mixtures are extremely abundant in the Universe, and diamond formation from them can play a crucial role in shaping the interior structure and evolution of planets. With first-principles accuracy, we first estimate the melting line of diamond, and then reveal the nature of chemical bonding in hydrocarbons at extreme conditions. We finally establish the pressure-temperature phase boundary where it is thermodynamically possible for diamond to form from hydrocarbon mixtures with different atomic fractions of carbon. Notably, here we show a depletion zone at pressures above 200 GPa and temperatures below 3000 K-3500 K where diamond formation is thermodynamically favorable regardless of the carbon atomic fraction, due to a phase separation mechanism. The cooler condition of the interior of Neptune compared to Uranus means that the former is much more likely to contain the depletion zone. Our findings can help explain the dichotomy of the two ice giants manifested by the low luminosity of Uranus, and lead to a better understanding of (exo-)planetary formation and evolution."}],"author":[{"id":"cbe3cda4-d82c-11eb-8dc7-8ff94289fcc9","first_name":"Bingqing","full_name":"Cheng, Bingqing","last_name":"Cheng","orcid":"0000-0002-3584-9632"},{"full_name":"Hamel, Sebastien","last_name":"Hamel","first_name":"Sebastien"},{"first_name":"Mandy","full_name":"Bethkenhagen, Mandy","last_name":"Bethkenhagen","orcid":"0000-0002-1838-2129","id":"201939f4-803f-11ed-ab7e-d8da4bd1517f"}],"citation":{"apa":"Cheng, B., Hamel, S., &#38; Bethkenhagen, M. (2023). Thermodynamics of diamond formation from hydrocarbon mixtures in planets. <i>Nature Communications</i>. Springer Nature. <a href=\"https://doi.org/10.1038/s41467-023-36841-1\">https://doi.org/10.1038/s41467-023-36841-1</a>","ieee":"B. Cheng, S. Hamel, and M. Bethkenhagen, “Thermodynamics of diamond formation from hydrocarbon mixtures in planets,” <i>Nature Communications</i>, vol. 14. Springer Nature, 2023.","chicago":"Cheng, Bingqing, Sebastien Hamel, and Mandy Bethkenhagen. “Thermodynamics of Diamond Formation from Hydrocarbon Mixtures in Planets.” <i>Nature Communications</i>. Springer Nature, 2023. <a href=\"https://doi.org/10.1038/s41467-023-36841-1\">https://doi.org/10.1038/s41467-023-36841-1</a>.","mla":"Cheng, Bingqing, et al. “Thermodynamics of Diamond Formation from Hydrocarbon Mixtures in Planets.” <i>Nature Communications</i>, vol. 14, 1104, Springer Nature, 2023, doi:<a href=\"https://doi.org/10.1038/s41467-023-36841-1\">10.1038/s41467-023-36841-1</a>.","ama":"Cheng B, Hamel S, Bethkenhagen M. Thermodynamics of diamond formation from hydrocarbon mixtures in planets. <i>Nature Communications</i>. 2023;14. doi:<a href=\"https://doi.org/10.1038/s41467-023-36841-1\">10.1038/s41467-023-36841-1</a>","ista":"Cheng B, Hamel S, Bethkenhagen M. 2023. Thermodynamics of diamond formation from hydrocarbon mixtures in planets. Nature Communications. 14, 1104.","short":"B. Cheng, S. Hamel, M. Bethkenhagen, Nature Communications 14 (2023)."},"publication_status":"published","publication_identifier":{"eissn":["2041-1723"]},"pmid":1,"_id":"12702","quality_controlled":"1","project":[{"name":"NOMIS Fellowship Program","_id":"9B861AAC-BA93-11EA-9121-9846C619BF3A"}],"oa_version":"Published Version","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","acknowledgement":"BC thanks Daan Frenkel for stimulating discussions. We thank Aleks Reinhardt, Daan Frenkel, Marius Millot, Federica Coppari, Rhys Bunting, and Chris J. Pickard for critically reading the manuscript and providing useful suggestions. BC acknowledges resources provided by the Cambridge Tier-2 system operated by the University of Cambridge Research Computing Service funded by EPSRC Tier-2 capital grant EP/P020259/1. SH acknowledges support from LDRD 19-ERD-031 and computing support from the Lawrence Livermore National Laboratory (LLNL) Institutional Computing Grand Challenge program. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344. MB acknowledges support by the European Horizon 2020 program within the Marie Skłodowska-Curie actions (xICE grant number 894725), funding from the NOMIS foundation and computational resources at the North-German Supercomputing Alliance (HLRN) facilities.","article_processing_charge":"No","oa":1,"volume":14,"date_updated":"2023-08-01T13:36:11Z","scopus_import":"1","publisher":"Springer Nature","language":[{"iso":"eng"}],"month":"02","date_published":"2023-02-27T00:00:00Z","article_type":"original","file":[{"file_id":"12713","creator":"cchlebak","content_type":"application/pdf","relation":"main_file","success":1,"date_updated":"2023-03-07T10:58:00Z","access_level":"open_access","date_created":"2023-03-07T10:58:00Z","checksum":"5ff61ad21511950c15abb73b18613883","file_name":"2023_NatComm_Cheng.pdf","file_size":1946443}],"date_created":"2023-03-05T23:01:04Z","has_accepted_license":"1","license":"https://creativecommons.org/licenses/by/4.0/","department":[{"_id":"BiCh"}],"intvolume":"        14","status":"public","day":"27","type":"journal_article","publication":"Nature Communications","file_date_updated":"2023-03-07T10:58:00Z"},{"title":"Ab initio calculation of the reflectivity of molecular fluids under shock compression","external_id":{"isi":["000974672600001"]},"doi":"10.1103/PhysRevB.107.134109","year":"2023","isi":1,"article_number":"134109","abstract":[{"text":"We calculate reflectivities of dynamically compressed water, water-ethanol mixtures, and ammonia at infrared and optical wavelengths with density functional theory and molecular dynamics simulations. The influence of the exchange-correlation functional on the results is examined in detail. Our findings indicate that the consistent use of the HSE hybrid functional reproduces experimental results much better than the commonly used PBE functional. The HSE functional offers not only a more accurate description of the electronic band gap but also shifts the onset of molecular dissociation in the molecular dynamics simulations to significantly higher pressures. We also highlight the importance of using accurate reference standards in reflectivity experiments and reanalyze infrared and optical reflectivity data from recent experiments. Thus, our combined theoretical and experimental work explains and resolves lingering discrepancies between calculations and measurements for the investigated molecular substances under shock compression.","lang":"eng"}],"author":[{"last_name":"French","full_name":"French, Martin","first_name":"Martin"},{"id":"201939f4-803f-11ed-ab7e-d8da4bd1517f","orcid":"0000-0002-1838-2129","full_name":"Bethkenhagen, Mandy","last_name":"Bethkenhagen","first_name":"Mandy"},{"full_name":"Ravasio, Alessandra","last_name":"Ravasio","first_name":"Alessandra"},{"first_name":"Jean Alexis","last_name":"Hernandez","full_name":"Hernandez, Jean Alexis"}],"publication_status":"published","citation":{"apa":"French, M., Bethkenhagen, M., Ravasio, A., &#38; Hernandez, J. A. (2023). Ab initio calculation of the reflectivity of molecular fluids under shock compression. <i>Physical Review B</i>. American Physical Society. <a href=\"https://doi.org/10.1103/PhysRevB.107.134109\">https://doi.org/10.1103/PhysRevB.107.134109</a>","ieee":"M. French, M. Bethkenhagen, A. Ravasio, and J. A. Hernandez, “Ab initio calculation of the reflectivity of molecular fluids under shock compression,” <i>Physical Review B</i>, vol. 107, no. 13. American Physical Society, 2023.","chicago":"French, Martin, Mandy Bethkenhagen, Alessandra Ravasio, and Jean Alexis Hernandez. “Ab Initio Calculation of the Reflectivity of Molecular Fluids under Shock Compression.” <i>Physical Review B</i>. American Physical Society, 2023. <a href=\"https://doi.org/10.1103/PhysRevB.107.134109\">https://doi.org/10.1103/PhysRevB.107.134109</a>.","mla":"French, Martin, et al. “Ab Initio Calculation of the Reflectivity of Molecular Fluids under Shock Compression.” <i>Physical Review B</i>, vol. 107, no. 13, 134109, American Physical Society, 2023, doi:<a href=\"https://doi.org/10.1103/PhysRevB.107.134109\">10.1103/PhysRevB.107.134109</a>.","ama":"French M, Bethkenhagen M, Ravasio A, Hernandez JA. Ab initio calculation of the reflectivity of molecular fluids under shock compression. <i>Physical Review B</i>. 2023;107(13). doi:<a href=\"https://doi.org/10.1103/PhysRevB.107.134109\">10.1103/PhysRevB.107.134109</a>","ista":"French M, Bethkenhagen M, Ravasio A, Hernandez JA. 2023. Ab initio calculation of the reflectivity of molecular fluids under shock compression. Physical Review B. 107(13), 134109.","short":"M. French, M. Bethkenhagen, A. Ravasio, J.A. Hernandez, Physical Review B 107 (2023)."},"_id":"13039","publication_identifier":{"issn":["2469-9950"],"eissn":["2469-9969"]},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","acknowledgement":"We thank R. Redmer for helpful discussions. M.F. acknowledges support by the Deutsche Forschungsgemeinschaft (DFG) within the FOR 2440. M.B. gratefully acknowledges support by the European Horizon 2020 programme within the Marie Skłodowska-Curie actions (xICE Grant No. 894725) and the NOMIS foundation. A.R. and J.-A.H. acknowledge support form the French National Research Agency (ANR) through the projects POMPEI (Grant No. ANR-16-CE31-0008) and SUPER-ICES (Grant No. ANR-15-CE30-008-01). The ab initio calculations were performed at the NorthGerman Supercomputing Alliance (HLRN) facilities. ","oa_version":"None","quality_controlled":"1","volume":107,"date_updated":"2023-08-01T14:45:25Z","article_processing_charge":"No","publisher":"American Physical Society","scopus_import":"1","language":[{"iso":"eng"}],"month":"04","article_type":"original","date_published":"2023-04-01T00:00:00Z","date_created":"2023-05-21T22:01:04Z","department":[{"_id":"BiCh"}],"intvolume":"       107","status":"public","day":"01","type":"journal_article","issue":"13","publication":"Physical Review B"}]