Caption: The x-ray laser investigates the change in the electron structure when CO molecules desorb from a metal surface of ruthenium. Roughly 30% of the molecules are pumped up with the aid of a femtosecond of optic laser from the surface-bonded (“chemisorbed”) state to a transient intermediate state (“precursor”) where they interact faintly with the surface. By examining the molecules with the x-ray laser with varying delay periods, it is possible to show that the time scale for achieving the precursor state is a few picoseconds and that they exist there for a few tens of picoseconds before either leaving the surface entirely or returning to the surface.
In the experiment, CO molecules were dosed onto a metal surface of ruthenium, which is used in automobile catalytic converters, for instance. CO binds strongly to the surface but can be made to let go by heating up the surface, which was done with a pulse from an optical laser. By starting the reaction for all the molecules at the same time, the team got a sufficient number of molecules to simultaneously enter a state where they have almost let go of the surface but still have a weak binding to it. From this short-lived state, the molecules can then continue out into a gas phase or renew their bond when the surface cools down again.“Scientists have long speculated whether such a state, a so-called ‘precursor,’ exists. The new experiment is the first to directly show its existence,” says Lars G. M. Pettersson at the Department of Physic, Stockholm University. These studies will not go on to more complex reactions of interest to the field of synthetic fuels, among other applications.
First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester
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24.05.2017 | Vienna University of Technology
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
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23.05.2017 | Event News
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26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy