Publications de Francesco Pennacchio

Ultrafast generation of hidden phases via energy-tuned electronic photoexcitation in magnetite

Fabrizio Carbone, Ivan Madan, Thomas La Grange, Benoît Guilhem Michel Binh Truc, Giovanni Maria Vanacore, Gabriele Berruto, Francesco Pennacchio, Paolo Usai

Phase transitions occurring in nonequilibrium conditions can evolve through high-energy intermediate states inaccessible via equilibrium adiabatic conditions. Because of the subtle nature of such hidden phases, their direct observation is extremely challen ...

National Academy of Sciences2024

Large variation in anti-SARS-CoV-2 antibody prevalence among essential workers in Geneva, Switzerland

Didier Trono, Idris Guessous, Francisco Javier Perez Saez, Francesco Pennacchio, Maria Eugenia Zaballa

Limited data exist on SARS-CoV-2 infection rates across sectors and occupations, hindering our ability to make rational policy, including vaccination prioritization, to protect workers and limit SARS-CoV-2 spread. Here, we present results from our SEROCoV- ...

Nature Research2021

Direct observation of photo-mechanical stiffness in alkanethiol-capped gold nanoparticles supracrystals by ultrafast small-angle electron diffraction

Francesco Stellacci, Fabrizio Carbone, Giulia Fulvia Mancini, Francesco Pennacchio, Tatiana Latychevskaia, Javier Reguera Gomez

We demonstrate that ultrastiff bonding between nanoparticles can be engineered by ad hoc assemblies of ligands, reaching strengths comparable to that of strong covalent bonds. Our observation relies on femtosecond small-angle electron diffraction. ...

E D P SCIENCES2019

Local photo-mechanical stiffness revealed in gold nanoparticles supracrystals by ultrafast small-angle electron diffraction

Francesco Stellacci, Fabrizio Carbone, Giulia Fulvia Mancini, Tatiana Latychevskaia, Javier Reguera Gomez, Francesco Pennacchio

We demonstrate that highly ordered two-dimensional crystals of ligand-capped gold nanoparticles display a local photo-mechanical stiffness as high as that of solids such as graphite. In out-of-equilibrium electron diffraction experiments, a strong temperat ...

2019

Spatio-temporal observation of dynamical structures in order-disorder phenomena and phase transitions via Ultrafast Electron Diffraction

Francesco Pennacchio

The development of ultrafast time-resolved techniques in the last decades allowed the direct observation of out-of-equilibrium transient states and dynamical processes up to then hidden in many different fields, ranging from chemistry to solid state physic ...

EPFL2018

Mapping the lattice dynamical anomaly of the order parameters across the Verwey transition in magnetite

Henrik Moodysson Rønnow, Fabrizio Carbone, Andrea Pisoni, Gregory Scott Tucker, Francesco Pennacchio, Simone Borroni

We present inelastic neutron scattering data across the Verwey transition in magnetite, obtained for a single crystal via a detwinning method. We provide direct evidence of the influence of the charge order on the transverse-acoustic phonons, associated wi ...

2017

Design and implementation of an optimal laser pulse front tilting scheme for ultrafast electron diffraction in reflection geometry with high temporal resolution

Fabrizio Carbone, Giulia Fulvia Mancini, Giovanni Maria Vanacore, Malte Oppermann, Francesco Pennacchio, Rajeswari Jayaraman

Ultrafast electron diffraction is a powerful technique to investigate out-of-equilibrium atomic dynamics in solids with high temporal resolution. When diffraction is performed in reflection geometry, the main limitation is the mismatch in group velocity be ...

Amer Inst Physics2017

Order/Disorder Dynamics in a Dodecanethiol-Capped Gold Nanoparticles Supracrystal by Small-Angle Ultrafast Electron Diffraction

Francesco Stellacci, Fabrizio Carbone, Giulia Fulvia Mancini, Tatiana Latychevskaia, Francesco Pennacchio, Javier Reguera Gomez

The design and the characterization of functionalized gold nanoparticles supracrystals require atomically resolved information on both the metallic core and the external organic ligand shell. At present, there is no known approach to characterize simultane ...

American Chemical Society2016