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548 results on '"Masciovecchio, C."'

204. Role of multilayer-like interference effects on the transient optical response of Si3N4 films pumped with free-electron laser pulses.

Author

Casolari, F., Bencivenga, F., Capotondi, F., Giangrisostomi, E., Manfredda, M., Mincigrucci, R., Pedersoli, E., Principi, E., Masciovecchio, C., and Kiskinova, M.

Subjects
SILICON films, FREE electron lasers, MULTILAYERED thin films, OPTICAL properties, REFRACTIVE index, TRANSMITTANCE (Physics)
Abstract

X-ray/optical cross-correlation methods are attracting increasing interest for exploring transient states of matter using ultrashort free-electron laser (FEL) pulses. Our paper shows that in such studies the difference in the penetration depth of the FEL-pump and the infrared (IR) probe pulses become important, in particular, when exploring the changes in the optical properties of solid targets. We discuss the role of interference effects, using a phenomenological model with excited and unperturbed slabs. The reliability of this model was experimentally verified by measuring the transient optical response of free-standing and silicon (Si) supported silicon nitride (Si3N4) films, simultaneously in reflection and transmission, using s- and p-polarized IR light. The changes in the Si3N4 optical refractive index, induced by the FEL pulses, have fully been described in the frame of the proposed model. The experimental results confirm that the differences, observed in the FEL-induced transient reflectance and transmittance of the Si3N4 targets with different thicknesses, arise from multilayer-like interferometric phenomena. [ABSTRACT FROM AUTHOR]

Published
2014
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207. Acoustic nature of the boson peak in vitreous silica

Author

Masciovecchio, C., primary, Mazzacurati, V., additional, Monaco, G., additional, Ruocco, G., additional, Scopigno, T., additional, Sette, F., additional, Benassi, P., additional, Cunsolo, A., additional, Fontana, A., additional, Krisch, M., additional, Mermet, A., additional, Montagna, M., additional, Rossi, F., additional, Sampoli, M., additional, Signorelli, G., additional, and Verbeni, R., additional

Published
1999
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209. High-frequency dynamics of glass-forming polybutadiene

Author

Fioretto, D., primary, Buchenau, U., additional, Comez, L., additional, Sokolov, A., additional, Masciovecchio, C., additional, Mermet, A., additional, Ruocco, G., additional, Sette, F., additional, Willner, L., additional, Frick, B., additional, Richter, D., additional, and Verdini, L., additional

Published
1999
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222. Benassiet al.Reply

Author

Benassi, P., primary, Krisch, M., additional, Masciovecchio, C., additional, Mazzacurati, V., additional, Monaco, G., additional, Ruocco, G., additional, Sette, F., additional, and Verbeni, R., additional

Published
1997
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226. Setteet al.Reply

Author

Sette, F., primary, Ruocco, G., additional, Krisch, M., additional, Masciovecchio, C., additional, Verbeni, R., additional, and Bergmann, U., additional

Published
1997
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233. Setteet al.Reply

Author

Sette, F., primary, Ruocco, G., additional, Krisch, M., additional, Bergmann, U., additional, Masciovecchio, C., additional, Mazzacurati, V., additional, Signorelli, G., additional, and Verbeni, R., additional

Published
1996
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236. X-ray Monochromator with 2 × 108 Energy Resolution

Author

Verbeni, R., primary, Sette, F., additional, Krisch, M. H., additional, Bergmann, U., additional, Gorges, B., additional, Halcoussis, C., additional, Martel, K., additional, Masciovecchio, C., additional, Ribois, J. F., additional, Ruocco, G., additional, and Sinn, H., additional

Published
1996
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241. Tracking Thermally Driven Molecular Reaction and Fragmentation by Fast Photoemission: C[sub 60] on Si(111).

Author

Goldoni, A., Larciprete, R., Cepek, C., Masciovecchio, C., El Mellouhi, F., Hudej, R., Sancrotti, M., and Paolucci, G.

Subjects
FULLERENES, SILICON, SPECTRUM analysis, PHOTOEMISSION
Abstract

We followed in real time the thermal reaction of fullerene molecules with the Si(111) surface by means of fast photoemission spectroscopy. The formation of SiC via C[sub 60] fragmentation on Si(111) is used as a key example of the capability of fast photoemission, associated with a fine temperature control, in determining the nature of thermally induced chemical reactions. By monitoring every 13 s the evolution of the C1s core level photoemission spectrum, as a function of temperature and as a function of time at fixed temperature, we were able to identify several steps in the interaction of C[sub 60] with Si(111). A model describing the thermal evolution of this interaction, in agreement with these and other experimental observations, considers the initial chemisorption of C[sub 60] in mainly metastable configurations, the evolution toward more stable configurations, allowed by molecular rotations and breaking of Si-Si bonds, the cage deformation to further increase the number of C-Si bonds, the final cage fragmentation and SiC formation only above 1050 ± 10 K. [ABSTRACT FROM AUTHOR]

Published
2002
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243. A new framework for soft x-ray transient gratings.

Author

Foglia, L, Mincigrucci, R, Doring, F, Fainozzi, D, Mamyrbayev, T, Masciovecchio, C, and Bencivenga, F

Subjects
*SOFT X rays, *DIFFRACTIVE optical elements, *FREE electron lasers, *ATTOSECOND pulses
Abstract

The capability to use extreme ultraviolet (EUV) light for generating transient gratings (TGs) has enabled the study of thermoelastic and magnetic dynamics at the nanoscale, in thin solid samples and surfaces, without the need of specially modifying them. However, the current mirror-based setup for generating EUV TG limits both its extension to the soft x-ray photon energy range and the attainment of few femtosecond time-resolution. Here we propose to overcome these limitations with an alternative experimental scheme based on diffractive optical elements that has become feasible with the current technology. In addition, some aspects of the discussed setup may facilitate the implementation of the EUV TG approach at table-top high-harmonic generation sources. [ABSTRACT FROM AUTHOR]

Published
2024
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246. Fermi@elettra status report

Author

Allaria, E., Bencivenga, F., Callegari, C., Capotondi, F., Castronovo, D., Cinquegrana, P., Cudin, I., Dal Forno, M., Danailov, M. B., D Auria, G., Monte, R., Ninno, G., Demidovich, A., Di Mitri, S., Diviacco, B., Fabris, A., Fabris, R., Fawley, W. M., Ferianis, M., Ferrari, E., Froehlich, L., Furlan Radivo, P., Gaio, G., Giannessi, L., Kiskinova, M., Lonza, M., Mahieu, B., Mahne, N., Masciovecchio, C., Fulvio Parmigiani, Penco, G., Predonzani, M., Principi, E., Raimondi, L., Rossi, F., Rumiz, L., Scafuri, C., Serpico, C., Sigalotti, P., Spampinati, S., Spezzani, C., Svandrlik, M., Svetina, C., Trovo, M., Vascotto, A., Veronese, M., Visintini, R., Zangrando, D., Zangrando, M., and Craievich, P.

247. X-ray diffraction and Raman scattering measurements on silica xerogels

Author

Caponi, S., Ferrari, M., Fontana, A., Masciovecchio, C., Mermet, A., Montagna, M., Rossi, F., Giancarlo Ruocco, and Sette, F.

Abstract

The dynamics and the structure of silica xerogels at different degrees of densification have been studied by small angle X-ray scattering and Raman scattering, with the aim to investigate the effects of the inhomogeneous structure on the excitations that give rise to the excess in the density of states (Boson peak). The results are compared with those of specific heat measurements on the same samples. The present results show that the existence of the pores, whose medium size is in the 30-60 A A range, does not appreciably affect the density of states in the Boson peak frequency range. On the contrary, at lower frequencies (x < 20 cm À1), a strong pore-size dependence is observed in the Raman spectra.

250. Spectral tuning of Extreme Ultraviolet Femtosecond Pulses driven by ultrafast nonlinear light-matter interactions

Author

Ferrante, C., Emiliano PRINCIPI, Marini, A., Batignani, G., Fumero, G., Virga, A., Foglia, L., Mincigrucci, R., Simoncig, A., Spezzani, C., Masciovecchio, C., and Scopigno, T.

Abstract

we have explored the sub-picosecond nonlinear response of metals in the extreme ultraviolet. Focusing high-fluence beams into submicrometric foils, we have shown how to exploit nonlinear optical effects for driving self-induced modulation of pulse spectra.

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