pini_2026 ========= M\. Pini, S\. Severino, L\. Mai, M\. Ortolan, D\. Mocci, L\. Colaizzi, N\. Kotsina, J\. Nordmann, C\. Brahms, J\. C\. Travers, M\. Lucchini, R\. Borrego\-Varillas, F\. Aleotti, A\. Nenov, M\. Reduzzi and M\. Nisoli, "3\-fs\-resolved UV/XUV photoelectron spectroscopy in the gas phase", Nat\. Commun\. 17, 9912 \(2026\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1038/s41467\-026\-76602\-4 `__ **Source kind:** measurement **Recorded technique:** UV\-pump, XUV\-probe time\-resolved photoelectron spectroscopy\: tunable \(230\-330 nm\) sub\-3\-fs UV pulses from resonant dispersive\-wave emission in an argon\- or neon\-filled hollow capillary fibre, isolated attosecond XUV pulses \(20\-45 eV\) from high\-harmonic generation in xenon, a time\-of\-flight electron spectrometer\. The instrument response is measured in situ by XUV\-UV sideband cross\-correlation in argon; the application is acetylacetone\. **Materials in structured entries:** None recorded. **Dataset quantities:** None recorded. **Contents:** 0 datasets; 0 formulas. Curation notes -------------- Pages are PDF pages \(article 9912, pp\. 1\-9\)\. Identity checked against the first page \(Nature Communications \(2026\) 17\:9912\)\. No supplementary information in the library\. NOTHING TAKEN\: the paper prints no two\-photon number for Kr or Xe, or for any gas\. Two\-photon ionisation of noble gases as an in\-situ characterisation is mentioned only by reference to andrade\_2025 \(Ref\. 14, p\. 2\); here the instrument response is the cross\-correlation of the first sideband \(one XUV photon plus one UV photon\) of argon photoelectrons\: 3\.2 \+\- 0\.2 fs FWHM with UV pulses centred near 278 nm \(4\.45 eV\), 200 nJ, 'estimated peak intensity of 7 x 10^11 W cm^\-2', XUV filtered by 200 nm of Sn \(pp\. 2\-3\)\. The sideband intensity 'scales as omega\_UV^\-4' in the linear regime \(Ref\. 35\), about 69 times weaker than at 800 nm for the same intensity \(p\. 3\)\: a statement of scaling, not a cross section\. Maximum UV peak intensity 1\.1e13 W/cm^2 \(neon\-filled fibre, 3 fs, focal spot 90 x 95 um at 1/e^2; p\. 7\)\. The UV pulse energies against wavelength are in the Supplementary Information, not in the library\. FURTHER TWO\-PHOTON DATA CITED\: none with values \(Ref\. 35, M\. Lucchini et al\., Nat\. Commun\. 13, 7103 \(2022\), for the sideband scaling\)\. **Recorded bibliographic identity status:** VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- No datasets are recorded. Formulas -------- No formulas are recorded. Corrections ----------- No dataset errata are recorded in this source record. Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register ` for the checks and decisions.