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data archive 10322 disk0/00/00/04/05 2017-04-27 15:35:16 2024-04-16 14:24:51 2017-04-28 10:54:06 data_collection show Peccianti M. Departement of Physics and Astronomy, University of Sussex, Brighton, UK Fastampa R. Dipartimento di Fisica, Università di Roma “Sapienza”, Roma, Italy Mosca Conte A. ETSF, Dipartimento di Fisica, Universitá di Roma Tor Vergata, Rome, Italy Pulci O. ETSF, Dipartimento di Fisica, Universitá di Roma Tor Vergata, Rome, Italy Violante C. ETSF, Dipartimento di Fisica, Universitá di Roma Tor Vergata, Rome, Italy Łojewska J. Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland Clerici Matteo 34943 0000-0002-9100-8539 Morandotti Roberto INRS-EMT, University of Quebec, Varennes, Quebec J3X 1S2, Canada Missori M. Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, UOS Sapienza, Roma, Italy glaresearchdata:2017-04-27-405 unpub 30300000 Artifacts made of cellulose, such as ancient documents, pose a significant experimental challenge in the THz transmission spectra interpretation due to their small optical thickness. In this Letter we describe a method to recover the complex refractive index of cellulose fibers from the THz transmission data obtained on single freely standing paper sheets in the 0.2–3.5 THz range. By using our technique, we were able to eliminate Fabry-Perot effects and recover the absorption coefficient of the cellulose fibers. The obtained THz absorption spectra are explained in terms of absorption peaks of the cellulose crystalline phase superimposed to a background contribution due to a disordered hydrogen bonds network. The comparison between the experimental spectra with THz vibrational properties simulated by density functional theory calculations confirms this interpretation. In addition, evident changes in THz absorption spectra are produced by natural and artificial aging on paper samples and the final stage of aging is characterized by a spectral profile with only two peaks at about 2.1 THz and 3.1 THz. These results could be used to provide a quantitative assessment of the state of preservation of cellulose artifacts. This dataset contains the data for figures 1 - 4 in the paper. 2017-04-27 submitted University of Glasgow 10.5525/gla.researchdata.405 Spreadsheet University of Glasgow 72747 1 Quantum-enhanced THz spectroscopy and imaging Matteo Clerici Engineering & Physical Sciences Research Council (EPSRC) EP/P009697/1 ENG - ENGINEERING ELECTRONICS & NANO ENG 77172 1 EPSRC-ISF 2016: Quantum-enhanced THz detectors Matteo Clerici Engineering & Physical Sciences Research Council (EPSRC) EP/P51133X/1 ENG - ENGINEERING ELECTRONICS & NANO ENG FALSE EN 2027-04-27 R FALSE FALSE http://eprints.gla.ac.uk/id/eprint/140780