Info message Ce contenu n'est pas disponible en français. Ne plus afficher ce message. Scientific Highlights Titel Datum Année Année201920182017201620152014201320122011201020092008 Mois Moisjanvierfévriermarsavrilmaijuinjuilletaoûtseptembreoctobrenovembredécembre 5 septembre 2019 Kinetics and Mechanism of Metal Nanoparticle Growth via Optical Extinction Spectroscopy and Computational Modeling: The Curious Case of Colloidal Gold An overarching computational framework unifying several optical theories to describe the temporal volution of gold nanoparticles (GNPs) during a seeded growth process is presented. To achieve this, we sed the inexpensive and widely available optical extinction spectroscopy, to obtain quantitative kinetic data. In situ spectra collected over a wide set of experimental conditions were regressed using the hysical model, calculating light extinction by ensembles of GNPs during the growth process. This model rovides temporal information on the size, shape, and concentration of the particles, and any electromagnetic interactions between them. Consequently, we were able to describe the mechanism of GNP growth and divide the process into distinct genesis periods. We provide explanations for several longstanding mysteries, e.g., the phenomena responsible for the purple-greyish hue during the early stages of GNP growth, the complex interactions between nucleation, growth and aggregation events, and a clear distinction between agglomeration and electromagnetic interactions. The presented theoretical formalism has been developed in a generic fashion so that it can readily be adapted to other nanoparticulate formation scenarios such as the genesis of various metal nanoparticles. 15 juillet 2019 Chemically mapping ice forming particles Scientists have just nucleated ice in an X-ray microscope for the first time and they created chemical maps of those responsible. 23 octobre 2018 Breakthrough - electron crystallography for everyone Recent advances in electron crystallography published in Angewandte Chemie and highlighted by Science, Chemical & Engineering News and ScienceNews!Under the lead of LSK member, "Rapid structure determination of microcrystalline molecular compounds using electron diffraction", published in Angewandte Chemie International Edition https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201811318 has attracted great attention in the chemistry community. 17 octobre 2018 Les causes de la fin du Petit Âge glaciaire au milieu du XIXe siècle Communiqués de presse Energie et environnement Environnement Au cours de la première moitié du XIXe siècle, une série de fortes éruptions volcaniques dans les Tropiques a provoqué temporairement un refroidissement global du climat terrestre. Le fait que les glaciers ont progressé pendant la phase finale du Petit Âge glaciaire, avant de reculer à nouveau, était un phénomène naturel. C’est ce qu’ont montré des chercheurs du PSI au moyen de carottes de glace. 29 juin 2018 Brennstoffzellen zum Durchbruch verhelfen Wasserstoff gilt als vielversprechende Alternative für eine Zukunft ohne fossile Energieträger. Um Brennstoffzellen weiterzuentwickeln und für einen Markteintritt vorzubereiten, verstärkt die Empa die Zusammenarbeit mit der H2 Energy Holding AG und dem Paul Scherrer Institut (PSI). 26 septembre 2017 Light from the particle accelerator helps to understand ozone decomposition PSI researchers have developed an experimental chamber in which they can recreate atmospheric processes and probe them with unprecedented precision, using X-ray light from the Swiss Light Source SLS. In the initial experiments, they have studied the production of bromine, which plays an essential role in the decomposition of ozone in the lower layers of the atmosphere. In the future, the new experiment chamber will also be available for use by researchers from other scientific fields. 21 septembre 2017 Coexistence of Physisorbed and Solvated HCl at Warm Ice Surfaces The interfacial ionization of strong acids is an essential factor of multiphase and heterogeneous chemistry in environmental science, cryospheric science, catalysis research and material science. Using Near Ambient Pressure X-ray Photoelectron (NAPP) spectroscopy, we directly detected a low surface coverage of adsorbed HCl at 253 K in both molecular and dissociated states and interpret the results as physisorbed molecular HCl at the outermost ice surface and dissociation occurring upon solvation deeper in the interfacial region. This study gives clear evidence for nonuniformity across the air−ice interface and questions the use of acid−base concepts in interfacial processes. 13 juillet 2017 Gasoline cars produce more carbonaceous particulate matter than modern filter-equipped diesel cars In contrast to nitrogen oxides, modern gasoline cars emit much more cancerogenic primary soot (black carbon + primary organic aerosol) and lead to more toxic secondary organic aerosol than modern diesel vehicles. 22 février 2017 Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Based on a 6500 year ice-core Cu record from Illimani glacier in Bolivia we provide the first complete history of large-scale Cu smelting activities in South America. Earliest anthropogenic Cu pollution was found during the Early Horizon period ~700-50 BC. We attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures. 1 2 3 4 Page suivante ›› Dernière page Last » Sidebar General Contact Research Div. Energy and Environment Paul Scherrer Institut 5232 Villigen-PSI Switzerland Head Prof. Dr. Thomas J. Schmidt Telephone: +41 56 310 57 65 E-mail: thomasjustus.schmidt@psi.ch ENE Staff Dr. Jörg Roth Telephone: +41 56 310 53 96 E-mail: joerg.roth@psi.ch M.Sc. Agnieszka Hamburger Telephone: +41 56 310 27 92 E-mail: agnieszka.hamburger@psi.ch Assistant Ursula Ludgate Telephone: +41 56 310 20 92 E-mail: ursula.ludgate@psi.ch ENE Open positions current opening at Research Division Energy and Environment ENE Events The Energy and Environment Research Division (ENE) hold a department seminar typically once a week during the semester on Thursdays at 11.00am.
5 septembre 2019 Kinetics and Mechanism of Metal Nanoparticle Growth via Optical Extinction Spectroscopy and Computational Modeling: The Curious Case of Colloidal Gold An overarching computational framework unifying several optical theories to describe the temporal volution of gold nanoparticles (GNPs) during a seeded growth process is presented. To achieve this, we sed the inexpensive and widely available optical extinction spectroscopy, to obtain quantitative kinetic data. In situ spectra collected over a wide set of experimental conditions were regressed using the hysical model, calculating light extinction by ensembles of GNPs during the growth process. This model rovides temporal information on the size, shape, and concentration of the particles, and any electromagnetic interactions between them. Consequently, we were able to describe the mechanism of GNP growth and divide the process into distinct genesis periods. We provide explanations for several longstanding mysteries, e.g., the phenomena responsible for the purple-greyish hue during the early stages of GNP growth, the complex interactions between nucleation, growth and aggregation events, and a clear distinction between agglomeration and electromagnetic interactions. The presented theoretical formalism has been developed in a generic fashion so that it can readily be adapted to other nanoparticulate formation scenarios such as the genesis of various metal nanoparticles.
15 juillet 2019 Chemically mapping ice forming particles Scientists have just nucleated ice in an X-ray microscope for the first time and they created chemical maps of those responsible.
23 octobre 2018 Breakthrough - electron crystallography for everyone Recent advances in electron crystallography published in Angewandte Chemie and highlighted by Science, Chemical & Engineering News and ScienceNews!Under the lead of LSK member, "Rapid structure determination of microcrystalline molecular compounds using electron diffraction", published in Angewandte Chemie International Edition https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201811318 has attracted great attention in the chemistry community.
17 octobre 2018 Les causes de la fin du Petit Âge glaciaire au milieu du XIXe siècle Communiqués de presse Energie et environnement Environnement Au cours de la première moitié du XIXe siècle, une série de fortes éruptions volcaniques dans les Tropiques a provoqué temporairement un refroidissement global du climat terrestre. Le fait que les glaciers ont progressé pendant la phase finale du Petit Âge glaciaire, avant de reculer à nouveau, était un phénomène naturel. C’est ce qu’ont montré des chercheurs du PSI au moyen de carottes de glace.
29 juin 2018 Brennstoffzellen zum Durchbruch verhelfen Wasserstoff gilt als vielversprechende Alternative für eine Zukunft ohne fossile Energieträger. Um Brennstoffzellen weiterzuentwickeln und für einen Markteintritt vorzubereiten, verstärkt die Empa die Zusammenarbeit mit der H2 Energy Holding AG und dem Paul Scherrer Institut (PSI).
26 septembre 2017 Light from the particle accelerator helps to understand ozone decomposition PSI researchers have developed an experimental chamber in which they can recreate atmospheric processes and probe them with unprecedented precision, using X-ray light from the Swiss Light Source SLS. In the initial experiments, they have studied the production of bromine, which plays an essential role in the decomposition of ozone in the lower layers of the atmosphere. In the future, the new experiment chamber will also be available for use by researchers from other scientific fields.
21 septembre 2017 Coexistence of Physisorbed and Solvated HCl at Warm Ice Surfaces The interfacial ionization of strong acids is an essential factor of multiphase and heterogeneous chemistry in environmental science, cryospheric science, catalysis research and material science. Using Near Ambient Pressure X-ray Photoelectron (NAPP) spectroscopy, we directly detected a low surface coverage of adsorbed HCl at 253 K in both molecular and dissociated states and interpret the results as physisorbed molecular HCl at the outermost ice surface and dissociation occurring upon solvation deeper in the interfacial region. This study gives clear evidence for nonuniformity across the air−ice interface and questions the use of acid−base concepts in interfacial processes.
13 juillet 2017 Gasoline cars produce more carbonaceous particulate matter than modern filter-equipped diesel cars In contrast to nitrogen oxides, modern gasoline cars emit much more cancerogenic primary soot (black carbon + primary organic aerosol) and lead to more toxic secondary organic aerosol than modern diesel vehicles.
22 février 2017 Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Based on a 6500 year ice-core Cu record from Illimani glacier in Bolivia we provide the first complete history of large-scale Cu smelting activities in South America. Earliest anthropogenic Cu pollution was found during the Early Horizon period ~700-50 BC. We attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.
