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1. Microscopic dynamics of gas molecules confined in porous channel-like ice structure.

Author

del Rosso, L., Colognesi, D., Donati, A., Rudić, S., and Celli, M.

Subjects
*GAS dynamics, *NEUTRON spectrometers, *MOLECULES
Abstract

In the rich ice polymorphism landscape, ice XVII, metastable at ambient pressure and at temperatures below 130 K, is surely one of the most interesting from both fundamental and technological perspectives due to its porosity, i.e., its capability to repeatedly absorb and desorb molecular hydrogen by dosing the gas at pressures even below the ambient one. Here, owing to this exceptional key feature, we investigate the roto-vibrational dynamics of the H2 molecules trapped in the fully deuterated ice XVII structure. Making use of the high-resolution and brilliance of the TOSCA neutron vibrational spectrometer, combined with high-resolution Raman data, we are able to efficiently distinguish the center-of-mass translational bands from the rotational ones and to study them as a function of the guest filling of the ice structure, unraveling a peculiar behavior for the confined particle in a low-dimensional system. Moreover, we also report the study of the microscopic dynamics of confined nitrogen and oxygen, which are the most abundant molecular species in the atmosphere and are of paramount interest for technological applications. Finally, we show that the ice XVII porosity is a unique feature, especially in the low pressure regime, within the emptied-hydrate phases discovered to date. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Velocity autocorrelation in liquid para-hydrogen by quantum simulations for first-principle computations of the neutron cross sections

Author

Guarini, E., Neumann, M., Bafile, U., Celli, M., Colognesi, D., Farhi, E., and Calzavara, Y.

Subjects
Condensed Matter - Disordered Systems and Neural Networks, Physics - Chemical Physics
Abstract

Accurate knowledge of the single-molecule (self) translational dynamics of liquid para-H2 is an essential requirement for the calculation of the neutron scattering properties of this important quantum liquid. We show that, by using Centroid Molecular Dynamics (CMD) quantum simulations of the velocity autocorrelation function, calculations of the total neutron cross section (TCS) remarkably agree with experimental data at the thermal and epithermal incident neutron energies where para-H2 dynamics is actually dominated by the self contributions. This result shows that a proper account of the quantum nature of the fluid, as provided by CMD, is a necessary and very effective condition to obtain the correct absolute-scale cross section values directly from first-principle computations of the double differential cross section, and without the need of introducing any empirically adjusted quantity. At subthermal incident energies, appropriate modeling of the para-H2 intermolecular (distinct) dynamics also becomes crucial, but quantum simulations are not yet able to cope with it. Existing simple models which account for the distinct part provide an appropriate correction of self-only calculations and bring the computed results in reasonable accord with TCS experimental data available until very recently. However, if just published cross section measurements in the cold range are considered, the agreement turns out to be by far superior and very satisfactory. The possible origin of slight residual differences will be commented and suggest further computational and experimental efforts. Nonetheless, the ability to reproduce the total cross section in the wide range between 1 and 900 meV represents an encouraging and important validation step of the CMD method and of the present simple algorithm.

Published
2015
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3. The instrument suite of the European Spallation Source

Author

Andersen, K.H., Argyriou, D.N, Jackson, A.J., Houston, J., Henry, P.F., Deen, P.P., Toft-Petersen, R., Beran, P., Strobl, M., Arnold, T., Wacklin-Knecht, H., Tsapatsaris, N., Oksanen, E., Woracek, R., Schweika, W., Mannix, D., Hiess, A., Kennedy, S., Kirstein, O., Petersson Årsköld, S., Taylor, J., Hagen, M.E., Laszlo, G., Kanaki, K., Piscitelli, F., Khaplanov, A., Stefanescu, I., Kittelmann, Th., Pfeiffer, D., Hall-Wilton, R., Lopez, C.I., Aprigliano, G., Whitelegg, L., Moreira, F.Y., Olsson, M., Bordallo, H.N., Martín-Rodríguez, D., Schneider, H., Sharp, M., Hartl, M., Nagy, G., Ansell, S., Pullen, S., Vickery, A., Fedrigo, A., Mezei, F., Arai, M., Heenan, R.K., Halcrow, W., Turner, D., Raspino, D., Orszulik, A., Cooper, J., Webb, N., Galsworthy, P., Nightingale, J., Langridge, S., Elmer, J., Frielinghaus, H., Hanslik, R., Gussen, A., Jaksch, S., Engels, R., Kozielewski, T., Butterweck, S., Feygenson, M., Harbott, P., Poqué, A., Schwaab, A., Lieutenant, K., Violini, N., Voigt, J., Brückel, T., Koenen, M., Kämmerling, H., Babcock, E., Salhi, Z., Wischnewski, A., Heynen, A., Désert, S., Jestin, J., Porcher, F., Fabrèges, X., Fabrèges, G., Annighöfer, B., Klimko, S., Dupont, Th., Robillard, Th., Goukassov, A., Longeville, S., Alba-Simionesco, Ch., Bourges, Ph., Guyon Le Bouffy, J., Lavie, P., Rodrigues, S., Calzada, E., Lerche, M., Schillinger, B., Schmakat, Ph., Schulz, M., Seifert, M., Lohstroh, W., Petry, W., Neuhaus, J., Loaiza, L., Tartaglione, A., Glavic, A., Schütz, S., Stahn, J., Lehmann, E., Morgano, M., Schefer, J., Filges, U., Klauser, Ch., Niedermayer, Ch., Fenske, J., Nowak, G., Rouijaa, M., Siemers, D.J., Kiehn, R., Müller, M., Carlsen, H., Udby, L., Lefmann, K., Birk, J.O., Holm-Dahlin, S., Bertelsen, M., Hansen, U. Bengaard, Olsen, M.A., Christensen, M., Iversen, K., Christensen, N.B., Rønnow, H.M., Freeman, P.G., Hauback, B.C., Kolevatov, R., Llamas-Jansa, I., Orecchini, A., Sacchetti, F., Petrillo, C., Paciaroni, A., Tozzi, P., Zanatta, M., Luna, P., Herranz, I., del Moral, O.G., Huerta, M., Magán, M., Mosconi, M., Abad, E., Aguilar, J., Stepanyan, S., Bakedano, G., Vivanco, R., Bustinduy, I., Sordo, F., Martínez, J.L., Lechner, R.E., Villacorta, F.J., Šaroun, J., Lukáš, P., Markó, M., Zanetti, M., Bellissima, S., del Rosso, L., Masi, F., Bovo, C., Chowdhury, M., De Bonis, A., Di Fresco, L., Scatigno, C., Parker, S.F., Fernandez-Alonso, F., Colognesi, D., Senesi, R., Andreani, C., Gorini, G., Scionti, G., and Schreyer, A.

Published
2020
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6. Quantum hydrogen vibrational dynamics in LiH: new neutron measurements and variational Monte Carlo simulations

Author

Boronat, J., Cazorla, C., Colognesi, D., and Zoppi, M.

Subjects
Condensed Matter - Materials Science
Abstract

Hydrogen single-particle dynamics in solid LiH at T=20 K has been studied through the incoherent inelastic neutron scattering technique. A careful analysis of the scattering data has allowed for the determination of a reliable hydrogen-projected density of phonon states and, from this, of three relevant physical quantities: mean squared displacement, mean kinetic energy, and Einstein frequency. In order to interpret these experimental findings, a fully-quantum microscopic calculation has been carried out using the variational Monte Carlo method. The agreement achieved between neutron scattering data and Monte Carlo estimates is good. In addition, a purely harmonic calculation has been also performed via the same Monte Carlo code, but anharmonic effects in H dynamics were not found relevant. The possible limitations of the present semi-empirical potentials are finally discussed., Comment: RevTex, 19 pages, accepted for publication in PRB

Published
2004
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7. Deep Inelastic Neutron Scattering determination of the single particle kinetic energy in solid and liquid 3He

Author

Senesi, R., Andreani, C., Colognesi, D., Cunsolo, A., and Nardone, M.

Subjects
Condensed Matter
Abstract

For the first time, an experimental determination of the single-particle mean kinetic energies for 3He along the T=2.00 K isotherm in the dense liquid and in the solid hcp and bcc phases is reported. Deep Inelastic Neutron Scattering measurements at exchanged wavevectors ranging from 90.0 A^-1 to 140.0 A^-1 have been performed in order to evaluate, within the framework of the Impulse Approximation, the molar volume dependence of the kinetic energy. The results are found in excellent agreement with recent Diffusion Monte Carlo simulations., Comment: RevTeX two column,4 pages, 2 figures, submitted to Phys. Rev. Lett

Published
2001
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14. Neutronic Calculations for the Shielding Design of the VESPA Instrument at the European Spallation Source

Author

Scionti, G, Agostino, R, Colognesi, D, Gorini, G, Hartl, M, Santoro, V, Senesi, R, Scionti G., Agostino R. G., Colognesi D., Gorini G., Hartl M., Santoro V., Senesi R., Scionti, G, Agostino, R, Colognesi, D, Gorini, G, Hartl, M, Santoro, V, Senesi, R, Scionti G., Agostino R. G., Colognesi D., Gorini G., Hartl M., Santoro V., and Senesi R.

Abstract

The European Spallation Source is being built in Lund, Sweden and it’s planned to be the brightest pulsed spallation source for thermal and cold neutrons (<1 eV). Neutrons will be produced by a 2 GeV accelerated proton beam hitting a tungsten target wheel, then they are moderated by liquid hydrogen and water based moderator system and delivered to 42 beam-ports. Neutrons are transported via reflections to a set of instruments connected to the beam-ports through neutron guides. Undesired fast neutrons can cause a radiation safety issue, since they can find their way down the beam-lines and thus generate a large dose. A designed shielding structure is needed to minimize such effect during the beam at the target phase. We present the results of neutronic calculations to optimize the guide shielding for the VESPA instrument.

Published
2020

15. The instrument suite of the European Spallation Source

Author

Andersen, K, Argyriou, D, Jackson, A, Houston, J, Henry, P, Deen, P, Toft-Petersen, R, Beran, P, Strobl, M, Arnold, T, Wacklin-Knecht, H, Tsapatsaris, N, Oksanen, E, Woracek, R, Schweika, W, Mannix, D, Hiess, A, Kennedy, S, Kirstein, O, Petersson Arskold, S, Taylor, J, Hagen, M, Laszlo, G, Kanaki, K, Piscitelli, F, Khaplanov, A, Stefanescu, I, Kittelmann, T, Pfeiffer, D, Hall-Wilton, R, Lopez, C, Aprigliano, G, Whitelegg, L, Moreira, F, Olsson, M, Bordallo, H, Martin-Rodriguez, D, Schneider, H, Sharp, M, Hartl, M, Nagy, G, Ansell, S, Pullen, S, Vickery, A, Fedrigo, A, Mezei, F, Arai, M, Heenan, R, Halcrow, W, Turner, D, Raspino, D, Orszulik, A, Cooper, J, Webb, N, Galsworthy, P, Nightingale, J, Langridge, S, Elmer, J, Frielinghaus, H, Hanslik, R, Gussen, A, Jaksch, S, Engels, R, Kozielewski, T, Butterweck, S, Feygenson, M, Harbott, P, Poque, A, Schwaab, A, Lieutenant, K, Violini, N, Voigt, J, Bruckel, T, Koenen, M, Kammerling, H, Babcock, E, Salhi, Z, Wischnewski, A, Heynen, A, Desert, S, Jestin, J, Porcher, F, Fabreges, X, Fabreges, G, Annighofer, B, Klimko, S, Dupont, T, Robillard, T, Goukassov, A, Longeville, S, Alba-Simionesco, C, Bourges, P, Guyon Le Bouffy, J, Lavie, P, Rodrigues, S, Calzada, E, Lerche, M, Schillinger, B, Schmakat, P, Schulz, M, Seifert, M, Lohstroh, W, Petry, W, Neuhaus, J, Loaiza, L, Tartaglione, A, Glavic, A, Schutz, S, Stahn, J, Lehmann, E, Morgano, M, Schefer, J, Filges, U, Klauser, C, Niedermayer, C, Fenske, J, Nowak, G, Rouijaa, M, Siemers, D, Kiehn, R, Muller, M, Carlsen, H, Udby, L, Lefmann, K, Birk, J, Holm-Dahlin, S, Bertelsen, M, Hansen, U, Olsen, M, Christensen, M, Iversen, K, Christensen, N, Ronnow, H, Freeman, P, Hauback, B, Kolevatov, R, Llamas-Jansa, I, Orecchini, A, Sacchetti, F, Petrillo, C, Paciaroni, A, Tozzi, P, Zanatta, M, Luna, P, Herranz, I, del Moral, O, Huerta, M, Magan, M, Mosconi, M, Abad, E, Aguilar, J, Stepanyan, S, Bakedano, G, Vivanco, R, Bustinduy, I, Sordo, F, Martinez, J, Lechner, R, Villacorta, F, Saroun, J, Lukas, P, Marko, M, Zanetti, M, Bellissima, S, del Rosso, L, Masi, F, Bovo, C, Chowdhury, M, De Bonis, A, Di Fresco, L, Scatigno, C, Parker, S, Fernandez-Alonso, F, Colognesi, D, Senesi, R, Andreani, C, Gorini, G, Scionti, G, Schreyer, A, Andersen K. H., Argyriou D. N., Jackson A. J., Houston J., Henry P. F., Deen P. P., Toft-Petersen R., Beran P., Strobl M., Arnold T., Wacklin-Knecht H., Tsapatsaris N., Oksanen E., Woracek R., Schweika W., Mannix D., Hiess A., Kennedy S., Kirstein O., Petersson Arskold S., Taylor J., Hagen M. E., Laszlo G., Kanaki K., Piscitelli F., Khaplanov A., Stefanescu I., Kittelmann T., Pfeiffer D., Hall-Wilton R., Lopez C. I., Aprigliano G., Whitelegg L., Moreira F. Y., Olsson M., Bordallo H. N., Martin-Rodriguez D., Schneider H., Sharp M., Hartl M., Nagy G., Ansell S., Pullen S., Vickery A., Fedrigo A., Mezei F., Arai M., Heenan R. K., Halcrow W., Turner D., Raspino D., Orszulik A., Cooper J., Webb N., Galsworthy P., Nightingale J., Langridge S., Elmer J., Frielinghaus H., Hanslik R., Gussen A., Jaksch S., Engels R., Kozielewski T., Butterweck S., Feygenson M., Harbott P., Poque A., Schwaab A., Lieutenant K., Violini N., Voigt J., Bruckel T., Koenen M., Kammerling H., Babcock E., Salhi Z., Wischnewski A., Heynen A., Desert S., Jestin J., Porcher F., Fabreges X., Fabreges G., Annighofer B., Klimko S., Dupont T., Robillard T., Goukassov A., Longeville S., Alba-Simionesco C., Bourges P., Guyon Le Bouffy J., Lavie P., Rodrigues S., Calzada E., Lerche M., Schillinger B., Schmakat P., Schulz M., Seifert M., Lohstroh W., Petry W., Neuhaus J., Loaiza L., Tartaglione A., Glavic A., Schutz S., Stahn J., Lehmann E., Morgano M., Schefer J., Filges U., Klauser C., Niedermayer C., Fenske J., Nowak G., Rouijaa M., Siemers D. J., Kiehn R., Muller M., Carlsen H., Udby L., Lefmann K., Birk J. O., Holm-Dahlin S., Bertelsen M., Hansen U. B., Olsen M. A., Christensen M., Iversen K., Christensen N. B., Ronnow H. M., Freeman P. G., Hauback B. C., Kolevatov R., Llamas-Jansa I., Orecchini A., Sacchetti F., Petrillo C., Paciaroni A., Tozzi P., Zanatta M., Luna P., Herranz I., del Moral O. G., Huerta M., Magan M., Mosconi M., Abad E., Aguilar J., Stepanyan S., Bakedano G., Vivanco R., Bustinduy I., Sordo F., Martinez J. L., Lechner R. E., Villacorta F. J., Saroun J., Lukas P., Marko M., Zanetti M., Bellissima S., del Rosso L., Masi F., Bovo C., Chowdhury M., De Bonis A., Di Fresco L., Scatigno C., Parker S. F., Fernandez-Alonso F., Colognesi D., Senesi R., Andreani C., Gorini G., Scionti G., Schreyer A., Andersen, K, Argyriou, D, Jackson, A, Houston, J, Henry, P, Deen, P, Toft-Petersen, R, Beran, P, Strobl, M, Arnold, T, Wacklin-Knecht, H, Tsapatsaris, N, Oksanen, E, Woracek, R, Schweika, W, Mannix, D, Hiess, A, Kennedy, S, Kirstein, O, Petersson Arskold, S, Taylor, J, Hagen, M, Laszlo, G, Kanaki, K, Piscitelli, F, Khaplanov, A, Stefanescu, I, Kittelmann, T, Pfeiffer, D, Hall-Wilton, R, Lopez, C, Aprigliano, G, Whitelegg, L, Moreira, F, Olsson, M, Bordallo, H, Martin-Rodriguez, D, Schneider, H, Sharp, M, Hartl, M, Nagy, G, Ansell, S, Pullen, S, Vickery, A, Fedrigo, A, Mezei, F, Arai, M, Heenan, R, Halcrow, W, Turner, D, Raspino, D, Orszulik, A, Cooper, J, Webb, N, Galsworthy, P, Nightingale, J, Langridge, S, Elmer, J, Frielinghaus, H, Hanslik, R, Gussen, A, Jaksch, S, Engels, R, Kozielewski, T, Butterweck, S, Feygenson, M, Harbott, P, Poque, A, Schwaab, A, Lieutenant, K, Violini, N, Voigt, J, Bruckel, T, Koenen, M, Kammerling, H, Babcock, E, Salhi, Z, Wischnewski, A, Heynen, A, Desert, S, Jestin, J, Porcher, F, Fabreges, X, Fabreges, G, Annighofer, B, Klimko, S, Dupont, T, Robillard, T, Goukassov, A, Longeville, S, Alba-Simionesco, C, Bourges, P, Guyon Le Bouffy, J, Lavie, P, Rodrigues, S, Calzada, E, Lerche, M, Schillinger, B, Schmakat, P, Schulz, M, Seifert, M, Lohstroh, W, Petry, W, Neuhaus, J, Loaiza, L, Tartaglione, A, Glavic, A, Schutz, S, Stahn, J, Lehmann, E, Morgano, M, Schefer, J, Filges, U, Klauser, C, Niedermayer, C, Fenske, J, Nowak, G, Rouijaa, M, Siemers, D, Kiehn, R, Muller, M, Carlsen, H, Udby, L, Lefmann, K, Birk, J, Holm-Dahlin, S, Bertelsen, M, Hansen, U, Olsen, M, Christensen, M, Iversen, K, Christensen, N, Ronnow, H, Freeman, P, Hauback, B, Kolevatov, R, Llamas-Jansa, I, Orecchini, A, Sacchetti, F, Petrillo, C, Paciaroni, A, Tozzi, P, Zanatta, M, Luna, P, Herranz, I, del Moral, O, Huerta, M, Magan, M, Mosconi, M, Abad, E, Aguilar, J, Stepanyan, S, Bakedano, G, Vivanco, R, Bustinduy, I, Sordo, F, Martinez, J, Lechner, R, Villacorta, F, Saroun, J, Lukas, P, Marko, M, Zanetti, M, Bellissima, S, del Rosso, L, Masi, F, Bovo, C, Chowdhury, M, De Bonis, A, Di Fresco, L, Scatigno, C, Parker, S, Fernandez-Alonso, F, Colognesi, D, Senesi, R, Andreani, C, Gorini, G, Scionti, G, Schreyer, A, Andersen K. H., Argyriou D. N., Jackson A. J., Houston J., Henry P. F., Deen P. P., Toft-Petersen R., Beran P., Strobl M., Arnold T., Wacklin-Knecht H., Tsapatsaris N., Oksanen E., Woracek R., Schweika W., Mannix D., Hiess A., Kennedy S., Kirstein O., Petersson Arskold S., Taylor J., Hagen M. E., Laszlo G., Kanaki K., Piscitelli F., Khaplanov A., Stefanescu I., Kittelmann T., Pfeiffer D., Hall-Wilton R., Lopez C. I., Aprigliano G., Whitelegg L., Moreira F. Y., Olsson M., Bordallo H. N., Martin-Rodriguez D., Schneider H., Sharp M., Hartl M., Nagy G., Ansell S., Pullen S., Vickery A., Fedrigo A., Mezei F., Arai M., Heenan R. K., Halcrow W., Turner D., Raspino D., Orszulik A., Cooper J., Webb N., Galsworthy P., Nightingale J., Langridge S., Elmer J., Frielinghaus H., Hanslik R., Gussen A., Jaksch S., Engels R., Kozielewski T., Butterweck S., Feygenson M., Harbott P., Poque A., Schwaab A., Lieutenant K., Violini N., Voigt J., Bruckel T., Koenen M., Kammerling H., Babcock E., Salhi Z., Wischnewski A., Heynen A., Desert S., Jestin J., Porcher F., Fabreges X., Fabreges G., Annighofer B., Klimko S., Dupont T., Robillard T., Goukassov A., Longeville S., Alba-Simionesco C., Bourges P., Guyon Le Bouffy J., Lavie P., Rodrigues S., Calzada E., Lerche M., Schillinger B., Schmakat P., Schulz M., Seifert M., Lohstroh W., Petry W., Neuhaus J., Loaiza L., Tartaglione A., Glavic A., Schutz S., Stahn J., Lehmann E., Morgano M., Schefer J., Filges U., Klauser C., Niedermayer C., Fenske J., Nowak G., Rouijaa M., Siemers D. J., Kiehn R., Muller M., Carlsen H., Udby L., Lefmann K., Birk J. O., Holm-Dahlin S., Bertelsen M., Hansen U. B., Olsen M. A., Christensen M., Iversen K., Christensen N. B., Ronnow H. M., Freeman P. G., Hauback B. C., Kolevatov R., Llamas-Jansa I., Orecchini A., Sacchetti F., Petrillo C., Paciaroni A., Tozzi P., Zanatta M., Luna P., Herranz I., del Moral O. G., Huerta M., Magan M., Mosconi M., Abad E., Aguilar J., Stepanyan S., Bakedano G., Vivanco R., Bustinduy I., Sordo F., Martinez J. L., Lechner R. E., Villacorta F. J., Saroun J., Lukas P., Marko M., Zanetti M., Bellissima S., del Rosso L., Masi F., Bovo C., Chowdhury M., De Bonis A., Di Fresco L., Scatigno C., Parker S. F., Fernandez-Alonso F., Colognesi D., Senesi R., Andreani C., Gorini G., Scionti G., and Schreyer A.

Abstract

An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of the European Spallation Source (ESS), and being made available to the neutron user community. The ESS neutron source consists of a high-power accelerator and target station, providing a unique long-pulse time structure of slow neutrons. The design considerations behind the time structure, moderator geometry and instrument layout are presented. The 15-instrument suite consists of two small-angle instruments, two reflectometers, an imaging beamline, two single-crystal diffractometers; one for macromolecular crystallography and one for magnetism, two powder diffractometers, and an engineering diffractometer, as well as an array of five inelastic instruments comprising two chopper spectrometers, an inverse-geometry single-crystal excitations spectrometer, an instrument for vibrational spectroscopy and a high-resolution backscattering spectrometer. The conceptual design, performance and scientific drivers of each of these instruments are described. All of the instruments are designed to provide breakthrough new scientific capability, not currently available at existing facilities, building on the inherent strengths of the ESS long-pulse neutron source of high flux, flexible resolution and large bandwidth. Each of them is predicted to provide world-leading performance at an accelerator power of 2 MW. This technical capability translates into a very broad range of scientific capabilities. The composition of the instrument suite has been chosen to maximise the breadth and depth of the scientific impact of the early years of the ESS, and provide a solid base for completion and further expansion of the facility.

Published
2020

16. Density and time scaling effects on the velocity autocorrelation function of quantum and classical dense fluid para-hydrogen.

Author

Bellissima, S., Neumann, M., Bafile, U., Colognesi, D., Barocchi, F., and Guarini, E.

Subjects
QUANTUM fluids, AUTOCORRELATION (Statistics), DIFFUSION coefficients, MONOTONIC functions, KINETIC energy
Abstract

We report the results of a ring polymer molecular dynamics study of the Kubo velocity autocorrelation function of a quantum fluid as para-hydrogen aimed at the comparison with its classical counterpart. Quite different density conditions were considered for both the classical and quantum cases, in order to compare the two systems before and after the dynamical crossover typically undergone by the velocity autocorrelation function (VAF) of fluids at densities around the triple point, where the shape of the function changes from a monotonic to an oscillatory behavior with a negative minimum. A detailed study of the phase diagram of classical para-hydrogen was necessary for a reasonable choice of the classical states to be taken into consideration, in the spirit of the classical principle of corresponding states. The shape of the quantum and classical VAF was thoroughly analyzed, exhibiting at all studied densities clear differences that might be taken as evidence of quantum effects. We show that these differences are substantially reduced by applying a state-dependent time scaling with respect to a reference time identified with the inverse of the collision rate. An even better coincidence in shape is found by comparing the two systems at slightly non-corresponding reduced densities, suggesting that the quantum system behaves almost like the classical one, but at systematically less dense reduced states of the latter. We also find an unexpected and quite interesting density trend of the collision rate of both classical and quantum para-hydrogen, which accounts for the effectiveness of the scaling throughout the explored density range. The mean kinetic energy and the diffusion coefficients are also discussed in some detail. [ABSTRACT FROM AUTHOR]

Published
2019
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17. Neutronic developments on TOSCA and VESPA: Progress to date

Author

Zanetti, M, Bellissima, S, del Rosso, L, Masi, F, Chowdhury, M, De Bonis, A, Di Fresco, L, Scatigno, C, Armstrong, J, Rudic, S, Parker, S, Hartl, M, Colognesi, D, Senesi, R, Andreani, C, Gorini, G, Fernandez-Alonso, F, Zanetti M., Bellissima S., del Rosso L., Masi F., Chowdhury M., De Bonis A., Di Fresco L., Scatigno C., Armstrong J., Rudic S., Parker S. F., Hartl M., Colognesi D., Senesi R., Andreani C., Gorini G., Fernandez-Alonso F., Zanetti, M, Bellissima, S, del Rosso, L, Masi, F, Chowdhury, M, De Bonis, A, Di Fresco, L, Scatigno, C, Armstrong, J, Rudic, S, Parker, S, Hartl, M, Colognesi, D, Senesi, R, Andreani, C, Gorini, G, Fernandez-Alonso, F, Zanetti M., Bellissima S., del Rosso L., Masi F., Chowdhury M., De Bonis A., Di Fresco L., Scatigno C., Armstrong J., Rudic S., Parker S. F., Hartl M., Colognesi D., Senesi R., Andreani C., Gorini G., and Fernandez-Alonso F.

Abstract

We report recent developments regarding the TOSCA (ISIS, UK) and VESPA (ESS, Sweden) neutron broadband chemical spectrometers, both joint ventures between CNR (IT) and ISIS (UK). TOSCA has seen the first major upgrade since it first became operational over fifteen years ago. The new design of the primary spectrometer, which exploits a state-of-the-art, high-m neutron guide and associated chopper system, is boosting the useful neutron flux by over an order of magnitude. Feasibility studies for an upgrade of the secondary spectrometer have been performed, outlining an additional order-of-magnitude gain in performance. In the case of VESPA, the novel characteristics and challenges arising from a long-pulse spallation source such as ESS are part of the drivers of the instrument design. For both the primary and secondary spectrometers, a detailed analysis of expected performance, supported by both simulations and analytical models, is being carried out, also capitalizing from experience on TOSCA. Indeed, for instrument design and optimization, extensive neutron-transport simulations and baseline studies of neutronic response have become a must, along with extensive benchmarking against much-needed experimental data. All these combined efforts represent the first opportunity to benchmark a broadband, high-resolution chemical spectrometer in terms of measured vs. simulated response.

Published
2019

29. The instrument suite of the European Spallation Source

Author

Swedish Research Council, Centre National de la Recherche Scientifique (France), Science and Technology Facilities Council (UK), European Commission, Andersen, K. H., Argyriou, D. N., Jackson, A. J., Houston, J., Henry, P. F., Deen, P. P., Toft-Petersen, R., Beran, P., Strobl, M., Arnold, T., Wacklin-Knecht, H., Tsapatsaris, N., Morgano, M., Schefer, J., Filges, U., Klauser, Ch., Niedermayer, Ch., Fenske, J., Nowak, G., Rouijaa, M., Siemers, D. J., Hagen, M. E., Kiehn, R., Oksanen, E., Müller, M., Carlsen, H., Udby, L., Lefmann, K., Birk, J. O., Holm-Dahlin, S., Bertelsen, M., Bengaard Hansen, U., Laszlo, G., Olsen, M. A., Christensen, M., Woracek, R., Iversen, K., Christensen, N. B., Rønnow, H. M., Freeman, P. G., Hauback, B. C., Kolevatov, R., Llamas-Jansa, I., Kanaki, K., Orecchini, A., Sacchetti, F., Petrillo, C., Schweika, W., Paciaroni, A., Tozzi, P., Zanatta, M., Luna, P., Herranz, I., Moral, O. G. del, Piscitelli, F., Huerta, M., Magán, M., Mosconi, M., Abad, E., Mannix, D., Aguilar, J., Stepanyan, S., Bakedano, G., Vivanco, R., Bustinduy, I., Khaplanov, A., Sordo, F., Martínez, J. L., Lechner, R. E., Villacorta, F. J., Šaroun, J., Hiess, A., Lukáš, P., Markó, M., Zanetti, M., Bellissima, S., Stefanescu, I., Rosso, L. del, Masi, F., Bovo, C., Chowdhury, M., De Bonis, A., Di Fresco, L., Kennedy, S., Scatigno, C., Parker, S. F., Fernández-Alonso, Félix, Kittelmann, Th., Colognesi, D., Senesi, R., Andreani, C., Gorini, G., Sciont, G., Schreyer, A., Kirstein, O., Petersson Årsköld, S., Taylor, J., Pfeiffer, D., Hall-Wilton, R., Lopez, C. I., Seifert, M., Aprigliano, G., Whitelegg, L., Moreira, F. Y., Olsson, M., Bordallo, Heloisa N., Martín-Rodríguez, D., Schneider, H., Sharp, M., Hartl, M., Nagy, G., Lohstroh, W., Ansell, S., Pullen, S., Vickery, A., Fedrigo, A., Mezei, F., Arai, M., Heenan, R. K., Halcrow, W., Turner, D., Raspino, D., Petry, W., Orszulik, A., Cooper, J., Webb, N., Galsworthy, P., Nightingale, J., Langridge, S., Elmer, J., Frielinghaus, H., Hanslik, R., Gussen, A., Neuhaus, J., Jaksch, S., Engels, R., Kozielewski, T., Butterweck, S., Feygenson, M., Harbott, P., Poqué, A., Schwaab, A., Lieutenant, K., Violini, N., Loaiza, L., Voigt, J., Brückel, Thomas, Koenen, M., Kämmerling, H., Babcock, E., Salhi, Z., Wischnewski, A., Heynen, A., Désert, S., Jestin, J., Tartaglione, A., Porcher, F., Fabrèges, X., Fabrèges, G., Annighöfer, B., Klimko, S., Dupont, Th., Robillard, Th., Goukassov, A., Longeville, S., Alba-Simionesco, Ch., Glavic, Artur G., Bourges, Ph., Guyon Le Bouffy, J., Lavie, P., Rodrigues, S., Calzada, E., Lerche, M., Schillinger, B., Schmakat, Ph., Schulz, M., Schütz, S., Stahn, J., Lehmann, E., Swedish Research Council, Centre National de la Recherche Scientifique (France), Science and Technology Facilities Council (UK), European Commission, Andersen, K. H., Argyriou, D. N., Jackson, A. J., Houston, J., Henry, P. F., Deen, P. P., Toft-Petersen, R., Beran, P., Strobl, M., Arnold, T., Wacklin-Knecht, H., Tsapatsaris, N., Morgano, M., Schefer, J., Filges, U., Klauser, Ch., Niedermayer, Ch., Fenske, J., Nowak, G., Rouijaa, M., Siemers, D. J., Hagen, M. E., Kiehn, R., Oksanen, E., Müller, M., Carlsen, H., Udby, L., Lefmann, K., Birk, J. O., Holm-Dahlin, S., Bertelsen, M., Bengaard Hansen, U., Laszlo, G., Olsen, M. A., Christensen, M., Woracek, R., Iversen, K., Christensen, N. B., Rønnow, H. M., Freeman, P. G., Hauback, B. C., Kolevatov, R., Llamas-Jansa, I., Kanaki, K., Orecchini, A., Sacchetti, F., Petrillo, C., Schweika, W., Paciaroni, A., Tozzi, P., Zanatta, M., Luna, P., Herranz, I., Moral, O. G. del, Piscitelli, F., Huerta, M., Magán, M., Mosconi, M., Abad, E., Mannix, D., Aguilar, J., Stepanyan, S., Bakedano, G., Vivanco, R., Bustinduy, I., Khaplanov, A., Sordo, F., Martínez, J. L., Lechner, R. E., Villacorta, F. J., Šaroun, J., Hiess, A., Lukáš, P., Markó, M., Zanetti, M., Bellissima, S., Stefanescu, I., Rosso, L. del, Masi, F., Bovo, C., Chowdhury, M., De Bonis, A., Di Fresco, L., Kennedy, S., Scatigno, C., Parker, S. F., Fernández-Alonso, Félix, Kittelmann, Th., Colognesi, D., Senesi, R., Andreani, C., Gorini, G., Sciont, G., Schreyer, A., Kirstein, O., Petersson Årsköld, S., Taylor, J., Pfeiffer, D., Hall-Wilton, R., Lopez, C. I., Seifert, M., Aprigliano, G., Whitelegg, L., Moreira, F. Y., Olsson, M., Bordallo, Heloisa N., Martín-Rodríguez, D., Schneider, H., Sharp, M., Hartl, M., Nagy, G., Lohstroh, W., Ansell, S., Pullen, S., Vickery, A., Fedrigo, A., Mezei, F., Arai, M., Heenan, R. K., Halcrow, W., Turner, D., Raspino, D., Petry, W., Orszulik, A., Cooper, J., Webb, N., Galsworthy, P., Nightingale, J., Langridge, S., Elmer, J., Frielinghaus, H., Hanslik, R., Gussen, A., Neuhaus, J., Jaksch, S., Engels, R., Kozielewski, T., Butterweck, S., Feygenson, M., Harbott, P., Poqué, A., Schwaab, A., Lieutenant, K., Violini, N., Loaiza, L., Voigt, J., Brückel, Thomas, Koenen, M., Kämmerling, H., Babcock, E., Salhi, Z., Wischnewski, A., Heynen, A., Désert, S., Jestin, J., Tartaglione, A., Porcher, F., Fabrèges, X., Fabrèges, G., Annighöfer, B., Klimko, S., Dupont, Th., Robillard, Th., Goukassov, A., Longeville, S., Alba-Simionesco, Ch., Glavic, Artur G., Bourges, Ph., Guyon Le Bouffy, J., Lavie, P., Rodrigues, S., Calzada, E., Lerche, M., Schillinger, B., Schmakat, Ph., Schulz, M., Schütz, S., Stahn, J., and Lehmann, E.

Abstract

An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of the European Spallation Source (ESS), and being made available to the neutron user community. The ESS neutron source consists of a high-power accelerator and target station, providing a unique long-pulse time structure of slow neutrons. The design considerations behind the time structure, moderator geometry and instrument layout are presented. The 15-instrument suite consists of two small-angle instruments, two reflectometers, an imaging beamline, two single-crystal diffractometers; one for macromolecular crystallography and one for magnetism, two powder diffractometers, and an engineering diffractometer, as well as an array of five inelastic instruments comprising two chopper spectrometers, an inverse-geometry single-crystal excitations spectrometer, an instrument for vibrational spectroscopy and a high-resolution backscattering spectrometer. The conceptual design, performance and scientific drivers of each of these instruments are described. All of the instruments are designed to provide breakthrough new scientific capability, not currently available at existing facilities, building on the inherent strengths of the ESS long-pulse neutron source of high flux, flexible resolution and large bandwidth. Each of them is predicted to provide world-leading performance at an accelerator power of 2 MW. This technical capability translates into a very broad range of scientific capabilities. The composition of the instrument suite has been chosen to maximise the breadth and depth of the scientific impact of the early years of the ESS, and provide a solid base for completion and further expansion of the facility.

Published
2020

38. UCANS-8 in Paris Eighth International Meeting of the Union for Compact Accelerator-Driven Neutron Sources

Author

Ott, Frédéric, Menelle, Alain, Alba-Simionesco, Christiane, Andersen, K.H., Argyriou, D.N, Jackson, A.J., Houston, J., Henry, P.F., Deen, P.P., Toft-Petersen, R., Beran, P., Strobl, M., Arnold, T., Wacklin-Knecht, H., Tsapatsaris, N., Oksanen, E., Woracek, R., Schweika, W., Mannix, D., Hiess, A., Kennedy, S., Kirstein, O., Petersson Årsköld, S., Taylor, J., Hagen, M.E., Laszlo, G., Kanaki, K., Piscitelli, F., Khaplanov, A., Stefanescu, I., Kittelmann, Th., Pfeiffer, D., Hall-Wilton, R., Lopez, C.I., Aprigliano, G., Whitelegg, L., Moreira, F.Y., Olsson, M., Bordallo, H.N., Martín-Rodríguez, D., Schneider, Henri, Sharp, M., Hartl, M., Nagy, G., Ansell, S., Pullen, S., Vickery, A., Fedrigo, A., Mezei, F., Arai, M., Heenan, R.K., Halcrow, W., Turner, D., Raspino, D., Orszulik, A., Cooper, J., Webb, N., Galsworthy, P., Nightingale, J., Langridge, S., Elmer, J., Frielinghaus, H., Hanslik, R., Gussen, A., Jaksch, S., Engels, R., Kozielewski, T., Butterweck, S., Feygenson, M., Harbott, P., Poqué, A., Schwaab, A., Lieutenant, K., Violini, N., Voigt, J., Brückel, T., Koenen, M., Kämmerling, H., Babcock, E., Salhi, Z., Wischnewski, A., Heynen, A., Désert, S., Jestin, J., Porcher, F., Fabrèges, Xavier, Fabrèges, G., Annighöfer, B., Klimko, S., Dupont, Th., Robillard, Th., Goukassov, A., Longeville, S., Alba-Simionesco, Ch., Bourges, Ph., Guyon Le Bouffy, J., Lavie, P., Rodrigues, S., Calzada, E., Lerche, M., Schillinger, B., Schmakat, Ph., Schulz, M., Seifert, M., Lohstroh, W., Petry, W., Neuhaus, J., Loaiza, L., Tartaglione, A., Glavic, A., Schütz, S., Stahn, J., Lehmann, E., Morgano, M., Schefer, J., Filges, U., Klauser, Ch., Niedermayer, Ch., Fenske, J., Nowak, G., Rouijaa, M., Siemers, D.J., Kiehn, R., Müller, M., Carlsen, H., Udby, L., Lefmann, K., Birk, J.O., Holm-Dahlin, S., Bertelsen, M., Hansen, U. Bengaard, Olsen, M.A., Christensen, M., Iversen, K., Christensen, N.B., Rønnow, H.M., Freeman, P.G., Hauback, B.C., Kolevatov, R., Llamas-Jansa, I., Orecchini, A., Sacchetti, F., Petrillo, C., Paciaroni, A., Tozzi, P., Zanatta, M., Luna, P., Herranz, I., del Moral, O.G., Huerta, M., Magán, M., Mosconi, M., Abad, E., Aguilar, J., Stepanyan, S., Bakedano, G., Vivanco, R., Bustinduy, I., Sordo, F., Martínez, J.L., Lechner, R.E., Villacorta, F.J., Šaroun, J., Lukáš, P., Markó, M., Zanetti, M., Bellissima, S., del Rosso, L., Masi, F., Bovo, C., Chowdhury, M., de Bonis, A., Di Fresco, L., Scatigno, C., Parker, S.F., Fernandez-Alonso, F., Colognesi, D., Senesi, R., Andreani, C., Gorini, G., Scionti, G., Schreyer, A., Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, 010308 nuclear & particles physics, Political science, 0103 physical sciences, Library science, Neutron source, [CHIM.MATE]Chemical Sciences/Material chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, ComputingMilieux_MISCELLANEOUS, Dozen
Abstract

The 8th international meeting of the Union for Compact Accelerator-Driven Neutron Sources (UCANS-8) was held in Paris, July 8–11, 2019. Over 140 participants from more than a dozen countries from v...

Published
2019
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42. Proton vibrational dynamics in lithium imide investigated through incoherent inelastic and Compton neutron scattering.

Author

Pietropaolo, A., Colognesi, D., Catti, M., Nale, A.-C., Adams, M. A., Ramirez-Cuesta, A. J., and Mayers, J.

Subjects
*PROTONS, *NEUTRON scattering, *COMPTON electrons, *IMIDES, *INELASTIC scattering, *TEMPERATURE effect, *MOMENTUM distributions, *VIBRATION (Mechanics)
Abstract

In the present study we report neutron spectroscopic measurements on polycrystalline lithium imide, namely, incoherent inelastic neutron scattering at 20 K, and neutron Compton scattering from 10 K up to room temperature. From the former technique the H-projected density of phonon states up to 100 meV is derived, while the latter works out the spherically averaged single-particle (i.e., H, Li, and N) momentum distributions and, from this, the mean kinetic energies. Only for H at the lowest investigated temperature, non-Gaussian components of its momentum distribution are detected. However, these components do not seem directly connected to the system anharmonicity, being fully compatible with the simple N-H bond anisotropy. Neutron data are also complemented by ab initio lattice dynamics simulations, both harmonic and, at room temperature, carried out in the framework of the so-called 'quantum colored noise thermostat' method. The single-particle mean kinetic energies in lithium imide as a function of temperature show a quite peculiar behavior at the moment not reproduced by ab initio lattice dynamics methods, at least as far as H and Li are concerned. As matter of fact, neither their low temperature values nor their temperature trends can be precisely explained in terms of standard phonon calculations. [ABSTRACT FROM AUTHOR]

Published
2012
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44. Signatures of quantum behavior in the microscopic dynamics of liquid hydrogen and deuterium.

Author

Cunsolo, A., Colognesi, D., Sampoli, M., Senesi, R., and Verbeni, R.

Subjects
*LIQUEFIED gases, *LIQUID hydrogen, *DEUTERIUM, *X-ray scattering, *MONTE Carlo method, *QUANTUM theory
Abstract

We discuss the microscopic dynamics and structure of liquid hydrogen and deuterium, as probed by inelastic x-ray scattering measurements. Samples are kept in corresponding thermodynamic conditions, at which classical systems are expected to exhibit the same dynamic and static responses. On the contrary, we observe clear differences revealing the onset of quantum deviations, both in the broadening of inelastic excitations and in the position of the first sharp diffraction peak. These features are discussed, compared to path-integral Monte Carlo simulations, and finally associated with the different de Broglie wavelengths of the two isotopes. [ABSTRACT FROM AUTHOR]

Published
2005
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45. Density of phonon states in solid parahydrogen from inelastic neutron scattering.

Author

Colognesi, D., Celli, M., and Zoppi, M.

Subjects
*PHONONS, *SCATTERING (Physics), *NEUTRON sources, *SPECTROMETERS, *QUANTUM chemistry, *MOLECULAR dynamics
Abstract

We have measured the inelastic neutron scattering spectrum of solid parahydrogen (at low pressure and T=13.3 K) using the thermal original spectrometer with cylindrical analyzers spectrometer at the ISIS pulsed neutron source (UK). From the experimental spectrum we have obtained the parahydrogen density of phonon states which has been compared with the estimates available in the literature. The present determination improves substantially the previous experimental scenario from the point of view of both statistics and accuracy. The comparison with the most recent estimate obtained from a quantum mechanical simulation of the molecular dynamics calls for an improvement of the computational methods. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2004
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46. Proton dynamics in supercritical water.

Author

Andreani, C., Colognesi, D., Degiorgi, E., and Ricci, M. A.

Subjects
*PROTON transfer reactions, *WATER, *PHYSICAL & theoretical chemistry
Abstract

An inelastic neutron scattering experiment has been performed on supercritical water at high momentum transfer, up to 90 Å[sup -1], in order to study single proton dynamics. The value of the proton mean kinetic energy has been extracted in the framework of the impulse approximation. The anisotropy of the proton momentum distribution inside a single water molecule is discussed. The extracted experimental mean kinetic energy is found in good agreement with the predictions of a harmonic model, under the assumptions of decoupling between translational, rotational and vibrational degrees of freedom. Differences emerge between our results and those obtained in a recent inelastic neutron scattering experiment on water in sub- and supercritical conditions. These differences are pointed out and examined in detail. © 2001 American Institute of Physics. [DOI: 10.1063/1.1420751]. [ABSTRACT FROM AUTHOR]

Published
2001
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48. The high energy-transfer region in neutron scattering vibrational spectra: What does it mean and what could it be useful for?

Author

Colognesi D.

Subjects
vibrational spectroscopy, Inelastic neutron scattering
Abstract

We analyze the high energy transfer part of a neutron scattering spectrum from a protonated molecular crystal measured on an inverse-geometry crystal-analyzer spectrometers like TOSCA or VISION. In spite of the little information available in this range, we show that it is possible to exploit it in order to perform a new normalization procedure. Then a simple free gas model based on the impulse approximation is presented, followed by approximate methods for quickly correcting experimental data for the main unwanted effects. At the end, a practical example based on solid urea data is presented and the new normalization procedure is tested comparing the results from two different scattering laws (one being the free gas model). The two normalization constants obtained turn out to be practically identical showing the reliability of the suggested approach.

Published
2017
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50. Hydrogen self-dynamics in liquid H2- D2 mixtures studied through inelastic neutron scattering

Author

Colognesi D., Bafile U., Celli M., Neumann M., and Orecchini A.

Subjects
Incoherent inelastic neutron scatterings, Diffusion in liquids
Abstract

We have measured the dynamic structure factor of liquid para-hydrogen mixed with normal deuterium (T=20 K) at two different concentration levels using incoherent inelastic neutron scattering. This choice has been made since the presence of D2 modifies the self-dynamics of H2 in a highly nontrivial way, acting both on its pseudophononic and its diffusive parts in a tunable way. After an accurate data reduction, recorded neutron spectra were studied through the modified Young and Koppel model and the H2 center-of-mass self-dynamics structure factor was finally extracted for the two mixtures. Some physical quantities (i.e., self-diffusion coefficient and mean kinetic energy) were determined and compared with accurate quantum calculations, which, in addition, also provided estimates of the velocity autocorrelation function for the H2 centers of mass. These estimates, in conjunction with the Gaussian approximation, were used to simulate the H2 center-of-mass self-dynamics structure factor in the same range as the experimental one. The agreement between measured and calculated spectra was globally good, but some discrepancies proved the unquestionable breakdown of the Gaussian approximation in these semiquantum systems at a level comparable to that already observed in pure liquid para-hydrogen.

Published
2015
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