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Preziosi E, Andreani C, Romanelli G, Senesi R. The correction of Inelastic Neutron Scattering data of organic samples using the Average Functional Group Approximation. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202227202005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The use of the Average Functional Group Approximation for self-shielding corrections at inelastic neutron spectrometers is discussed. By taking triptindane as a case study, we use the above-mentioned approximation to simulate a synthetic dynamic structure factor as measured on an indirect-geometry spectrometer, as well as the related total scattering cross section as a function of incident neutron energy and sample temperature, and the transmission spectra depending on the sample thickness. These quantities, obtained in a consistent way from the Average Functional Group Approximation, are used to calculate the energy-dependent self-shielding correction affecting the sample under investigation. The impact on the intensities of low-energy vibrational modes is discussed, showing that at typical experimental conditions the sample-dependent attenuation factor is about 15% higher compared to the correction at higher energies.
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Glass Transition in Rice Pasta as Observed by Combined Neutron Scattering and Time-Domain NMR. Polymers (Basel) 2021; 13:polym13152426. [PMID: 34372027 PMCID: PMC8347043 DOI: 10.3390/polym13152426] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 12/18/2022] Open
Abstract
Experimental protocols aiming at the characterisation of glass transition often suffer from ambiguity. The ambition of the present study is to describe the glass transition in a complex, micro heterogeneous system, the dry rice pasta, in a most unambiguous manner, minimising the influence of technique-specific bias. To this end, we apply an unprecedented combination of experimental techniques. Apart from the usually used NMR and DSC, we employ, in a concurrent manner, neutron transmission, diffraction, and Compton scattering. This enables us to investigate the glass transition over a range of spatio-temporal scales that stretches over seven orders of magnitude. The results obtained by neutron diffraction and DSC reveal that dry rice pasta is almost entirely amorphous. Moreover, the glass transition is evidenced by neutron transmission and diffraction data and manifested as a significant decrease of the average sample number density in the temperature range between 40 and 60 °C. At the microscopic level, our NMR, neutron transmission and Compton scattering results provide evidence of changes in the secondary structure of the starch within the dry rice pasta accompanying the glass transition, whereby the long-range order provided by the polymer structure within the starch present in the dry rice pasta is partially lost.
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Romanelli G, Onorati D, Ulpiani P, Cancelli S, Perelli-Cippo E, Márquez Damián JI, Capelli SC, Croci G, Muraro A, Tardocchi M, Gorini G, Andreani C, Senesi R. Thermal neutron cross sections of amino acids from average contributions of functional groups. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:285901. [PMID: 33906173 DOI: 10.1088/1361-648x/abfc13] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/27/2021] [Indexed: 06/12/2023]
Abstract
The experimental thermal neutron cross sections of the 20 proteinogenic amino acids have been measured over the incident-neutron energy range spanning from 1 meV to 10 keV and data have been interpreted using the multi-phonon expansion based on first-principles calculations. The scattering cross section, dominated by the incoherent inelastic contribution from the hydrogen atoms, can be rationalised in terms of the average contributions of different functional groups, thus neglecting their correlation. These results can be used for modelling the total neutron cross sections of complex organic systems like proteins, muscles, or human tissues from a limited number of starting input functions. This simplification is of crucial importance for fine-tuning of transport simulations used in medical applications, including boron neutron capture therapy as well as secondary neutrons-emission induced during proton therapy. Moreover, the parametrized neutron cross sections allow a better treatment of neutron scattering experiments, providing detailed sample self-attenuation corrections for a variety of biological and soft-matter systems.
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Affiliation(s)
- Giovanni Romanelli
- ISIS Neutron and Muon Source, UKRI-STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Dalila Onorati
- Università degli Studi di Roma 'Tor Vergata', Dipartimento di Fisica and NAST Centre, Via della Ricerca Scientifica 1, Roma 00133, Italy
| | - Pierfrancesco Ulpiani
- Università degli Studi di Roma 'Tor Vergata', Dipartimento di Scienze e Tecnologie Chimiche, Via della Ricerca Scientifica 1, Roma 00133, Italy
| | | | | | | | - Silvia C Capelli
- ISIS Neutron and Muon Source, UKRI-STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Gabriele Croci
- Università di Milano-Bicocca, Piazza della Scienza 3, Milano, Italy
- Istituto per la Scienza e Tecnologia dei Plasmi, CNR, via Cozzi 53, 20125 Milano, Italy
| | - Andrea Muraro
- Istituto per la Scienza e Tecnologia dei Plasmi, CNR, via Cozzi 53, 20125 Milano, Italy
| | - Marco Tardocchi
- Istituto per la Scienza e Tecnologia dei Plasmi, CNR, via Cozzi 53, 20125 Milano, Italy
| | - Giuseppe Gorini
- Università di Milano-Bicocca, Piazza della Scienza 3, Milano, Italy
| | - Carla Andreani
- Università degli Studi di Roma 'Tor Vergata', Dipartimento di Fisica and NAST Centre, Via della Ricerca Scientifica 1, Roma 00133, Italy
- CNR-ISM, Area della Ricerca di Roma Tor Vergata, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Roberto Senesi
- Università degli Studi di Roma 'Tor Vergata', Dipartimento di Fisica and NAST Centre, Via della Ricerca Scientifica 1, Roma 00133, Italy
- CNR-IPCF, Sezione di Messina, Viale Ferdinando Stagno d'Alcontres 37, Messina, 98158, Italy
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Ulpiani P, Romanelli G, Onorati D, Krzystyniak M, Andreani C, Senesi R. The effective isotropy of the hydrogen local potential in biphenyl and other hydrocarbons. J Chem Phys 2020; 153:234306. [PMID: 33353342 DOI: 10.1063/5.0029578] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present an experimental investigation of the hydrogen nuclear momentum distribution in biphenyl using deep inelastic neutron scattering. Our experimental results suggest that the local potential affecting hydrogen is both harmonic and isotropic within experimental uncertainties. This feature is interpreted as a consequence of the central limit theorem, whereby the three-dimensional momentum distribution is expected to become a purely Gaussian function as the number of independent vibrational modes in a system increases. We also performed ab initio phonon calculations on biphenyl and other saturated hydrocarbons, from methane to decane. From the results of the simulations, one can observe that the nuclear momentum distribution becomes more isotropic as the number of atoms and normal modes in the molecule increases. Moreover, the predicted theoretical anisotropy in biphenyl is clearly larger than in the experiment. The reason is that the total number of normal modes necessary to reproduce the experimental results is much larger than the number of normal modes encompassed by a single unit cell due to the presence of structural disorder and intermolecular interactions in the real crystal, as well as coupling of different normal modes. Finally, experimental data were collected, over a subset of detectors on the VESUVIO spectrometer at ISIS, with a novel setup to increase the count rate and signal-to-background ratio. We envision that such an optimized experimental setup can provide faster measurements and more stringent constraints for phonon calculations.
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Affiliation(s)
- Pierfrancesco Ulpiani
- Università degli Studi di Roma "Tor Vergata," Dipartimento di Scienze e Tecnologie Chimiche, Via della Ricerca Scientifica 1, Rome 00133, Italy
| | - Giovanni Romanelli
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11OQX, United Kingdom
| | - Dalila Onorati
- Università degli Studi di Roma "Tor Vergata," Dipartimento di Fisica and NAST Center, Via della Ricerca Scientifica 1, Rome 00133, Italy
| | - Matthew Krzystyniak
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11OQX, United Kingdom
| | - Carla Andreani
- Università degli Studi di Roma "Tor Vergata," Dipartimento di Fisica and NAST Center, Via della Ricerca Scientifica 1, Rome 00133, Italy
| | - Roberto Senesi
- Università degli Studi di Roma "Tor Vergata," Dipartimento di Fisica and NAST Center, Via della Ricerca Scientifica 1, Rome 00133, Italy
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Bocedi A, Romanelli G, Andreani C, Senesi R. Hydrogen nuclear mean kinetic energy in water down the Mariana Trench: Competition of pressure and salinity. J Chem Phys 2020; 153:134306. [PMID: 33032407 DOI: 10.1063/5.0021926] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Mariana Trench is one of the most famous and extreme environments on our planet. We report experimental values of the hydrogen nuclear mean kinetic energy in water samples at the same physical and chemical conditions than in the Challenger Deep within the Mariana Trench: a pressure of 1092 bars, a temperature of 1 °C, and a salinity of 35 g of salt per kg of water. Results were obtained by deep inelastic neutron scattering at the VESUVIO spectrometer at ISIS. We find that the effect of pressure is to increase the hydrogen nuclear mean kinetic energy with respect to ambient conditions, while ions in the solution have the opposite effect. These results confirm the recent state-of-the-art simulations of the nuclear hydrogen dynamics in water. The changes in the nuclear mean kinetic energy likely correspond to different isotopic fractionation values in the Challenger Deep compared to standard sea water.
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Affiliation(s)
- Alessio Bocedi
- Università degli Studi di Roma "Tor Vergata", Dipartimento di Scienze e Tecnologie Chimiche, Via della Ricerca Scientifica 1, Rome 00133, Italy
| | - Giovanni Romanelli
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11OQX, United Kingdom
| | - Carla Andreani
- Università degli Studi di Roma "Tor Vergata", Dipartimento di Fisica and NAST Center, Via della Ricerca Scientifica 1, Rome 00133, Italy
| | - Roberto Senesi
- Università degli Studi di Roma "Tor Vergata", Dipartimento di Fisica and NAST Center, Via della Ricerca Scientifica 1, Rome 00133, Italy
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Festa G, Romanelli G, Senesi R, Arcidiacono L, Scatigno C, Parker SF, Marques MPM, Andreani C. Neutrons for Cultural Heritage-Techniques, Sensors, and Detection. SENSORS (BASEL, SWITZERLAND) 2020; 20:E502. [PMID: 31963186 PMCID: PMC7014385 DOI: 10.3390/s20020502] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/09/2020] [Accepted: 01/13/2020] [Indexed: 01/08/2023]
Abstract
Advances in research in Cultural Heritage see increasing application of a multidisciplinary approach and the combined use of physical and chemical characterization of artefacts that can be used to define their structure and their state of conservation, also providing valuable information in selecting the most suitable microclimatic conditions for the exhibition environment. This approach provides a platform for a synergic collaboration amongst researchers, restorers, conservators, and archaeologists. Existing state-of-the-art technologies for neutron-based methods are currently being applied to the study of objects of historical and cultural interest in several neutron-beam facilities around the world. Such techniques are non-invasive and non-destructive and are, therefore, ideal to provide structural information about artefacts, such as their composition, presence of alterations due to the environmental conditions, inclusions, structure of the bulk, manufacturing techniques, and elemental composition, which provide an overall fingerprint of the object's characteristics, thanks to the nature of the interaction of neutrons with matter. Here, we present an overview of the main neutron methods for the characterization of materials of interest in Cultural Heritage and we provide a brief introduction to the sensors and detectors that are used in this framework. We conclude with some case studies underlining the impact of these applications in different archaeological and historical contexts.
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Affiliation(s)
- Giulia Festa
- CENTRO FERMI—Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 1, 00184 Rome, Italy; (G.F.); (R.S.); (C.S.); (C.A.)
| | - Giovanni Romanelli
- ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK;
| | - Roberto Senesi
- CENTRO FERMI—Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 1, 00184 Rome, Italy; (G.F.); (R.S.); (C.S.); (C.A.)
- NAST Centre and Physics Department, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca, Scientifica 1, 00133, Rome, Italy
- CNR-IPCF Sezione di Messina, Viale Ferdinando Stagno d’Alcontres 37, 98158 Messina, Italy
| | - Laura Arcidiacono
- Diamond Light Source, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0DE, UK;
- UCL, University College of London Institute of Archaeology, 31-34 Gordon Square, Kings Cross, London WC1H 0PY, UK
| | - Claudia Scatigno
- CENTRO FERMI—Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 1, 00184 Rome, Italy; (G.F.); (R.S.); (C.S.); (C.A.)
- NAST Centre and Physics Department, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca, Scientifica 1, 00133, Rome, Italy
| | - Stewart F. Parker
- ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK;
| | - M. P. M. Marques
- Química-Física Molecular, University of Coimbra, 3004-535 Coimbra, Portugal;
- Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - Carla Andreani
- CENTRO FERMI—Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 1, 00184 Rome, Italy; (G.F.); (R.S.); (C.S.); (C.A.)
- NAST Centre and Physics Department, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca, Scientifica 1, 00133, Rome, Italy
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