Double-core-hole resonance spectroscopy at the iron L-edge of iron pentacarbonyl

Double-core-hole resonance spectroscopy at the iron L-edge of iron pentacarbonyl | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Double-core-hole resonance spectroscopy at the iron L -edge of iron pentacarbonyl Julius Schwarz, Thomas Baumann, Alberto De Fanis, Simon Dold, and 16 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9246555/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Transition-metal complexes are central for catalysis, material sciences and biochemistry, owing to their diverse non-radiative decay pathways driven by femtosecond-scale metal-ligand charge transfer. Resonant double-core-hole (DCH) ion-yield spectroscopy enables direct observation of ultrafast electronic and nuclear dynamics of such complexes with a direct coupling between strongly localized, transient charges and the chemically active valence electrons. Yet, previous DCH investigations were confined to atoms and small molecules at the K -edge. Here, we extend resonant DCH ion-yield spectroscopy to the L -edge of the transition-metal carbonyl Fe(CO) 5 in the gas phase to investigate fragmentation dynamics and sequential DCH ionization of the Fe center. Using intense femtosecond X-ray pulses, we observe signatures of multiply charged Fe cations, up to Fe 15+ . Comparison with atomic-level ionization-pathway modeling indicates a photon-energy range between 740eV and 780eV in which cations originating from core-excited DCH states dominate. Competing DCH channels, (i) resonant excitation following ionization or (ii) resonant-resonant excitation, govern the ionization and subsequent relaxation cascade. These channels enable charge build-up far beyond the single-core-hole (SCH) limit and induce fluence-dependent depletion of lower-charge fragments. Our results establish L -edge DCH resonance spectroscopy as a powerful approach for probing ultrafast charge redistribution and fragmentation in transition-metal complexes. Physical sciences/Physics/Atomic and molecular physics/Atomic and molecular interactions with photons Physical sciences/Chemistry/Physical chemistry/Chemical physics Full Text Additional Declarations There is NO Competing Interest. Supplementary Files DoublecoreholeresonancespectroscopyattheironLedgeofironpentacarbonylSI.pdf Supplementary Information Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9246555","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":620984952,"identity":"0122f968-c8d3-4970-bc91-74cbc198222b","order_by":0,"name":"Julius 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pentacarbonyl","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-9246555/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9246555/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Transition-metal complexes are central for catalysis, material sciences and biochemistry, owing to their diverse non-radiative decay pathways driven by femtosecond-scale metal-ligand charge transfer. \r\nResonant double-core-hole (DCH) ion-yield spectroscopy enables direct observation of ultrafast electronic and nuclear dynamics of such complexes with a direct coupling between strongly localized, transient charges and the chemically active valence electrons. Yet, previous DCH investigations were confined to atoms and small molecules at the \u003ci\u003eK\u003c/i\u003e-edge.\r\n Here, we extend resonant DCH ion-yield spectroscopy to the \u003ci\u003eL\u003c/i\u003e-edge of the transition-metal carbonyl Fe(CO)\u003csub\u003e5\u003c/sub\u003e in the gas phase to investigate fragmentation dynamics and sequential DCH ionization of the Fe center. Using intense femtosecond X-ray pulses, we observe signatures of multiply charged Fe cations, up to Fe\u003csup\u003e15+\u003c/sup\u003e. Comparison with atomic-level ionization-pathway modeling indicates a photon-energy range between 740eV and 780eV in which cations originating from core-excited DCH states dominate. Competing DCH channels, (i) resonant excitation following ionization or (ii) resonant-resonant excitation, govern the ionization and subsequent relaxation cascade. These channels enable charge build-up far beyond the single-core-hole (SCH) limit and induce fluence-dependent depletion of lower-charge fragments. Our results establish \u003ci\u003eL\u003c/i\u003e-edge DCH resonance spectroscopy as a powerful approach for probing ultrafast charge redistribution and fragmentation in transition-metal complexes.","manuscriptTitle":"Double-core-hole resonance spectroscopy at the iron L-edge of iron pentacarbonyl","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-14 04:27:36","doi":"10.21203/rs.3.rs-9246555/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7451f56f-7b28-4d50-98cd-be6cef8d8f0d","owner":[],"postedDate":"April 14th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"This content is not available.","date":"2026-05-06T17:52:45+00:00","index":2,"fulltext":"This content is not available."}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":66090247,"name":"Physical sciences/Physics/Atomic and molecular physics/Atomic and molecular interactions with photons"},{"id":66090248,"name":"Physical sciences/Chemistry/Physical chemistry/Chemical physics"}],"tags":[],"updatedAt":"2026-04-14T04:27:36+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-14 04:27:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9246555","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9246555","identity":"rs-9246555","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}