Fondements de la nature

A l’Institut Paul Scherrer, les scientifiques cherchent des réponses à la question essentielle des structures élémentaires de la matière et des principes fondamentaux de fonctionnement dans la nature. Ils étudient la structure et les propriétés des particules élémentaires – les plus petits composants de la matière – ou se penchent sur la question de savoir comment les molécules biologiques sont structurées et remplissent leur fonction. Les connaissances qu’ils acquièrent de la sorte ouvrent de nouvelles pistes de solution en sciences, en médecine ou dans le domaine des technologies.

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Watching atoms move

A complete characterization of the unit cell dynamics of a laser-excited tellurium crystal is demonstrated using femtosecond x-ray diffraction. The analysis offers a quantitative measure of the unit cell dynamics without making any assumptions on the symmetry of the excited-state motion.

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Confinement-Induced Orientational Alignment of Quasi-2D Fluids

Extreme confinement is known to induce ordering of the fluid, thereby affecting its properties.

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Advanced phase contrast imaging using a grating interferometer

Conventional absorption based X-ray microtomography can become limited for objects showing only very weak attenuation contrast at high energies. However, a wide range of samples studied in biology and materials science can produce significant phase shifts of the X-ray beam and thus phase contrast X-ray imaging can provide substantially increased contrast sensitivity.

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Electrons with opposite spins move in opposite directions

In one dimension, there are only two ways to move: left or right. This leads to some peculiar properties for one-dimensional systems on the atomic scale.

Phonon squeezing

Photon squeezing has been the subject of intense interest in the field of quantum optics, since it serves as a unique demonstration of the quantum nature of light. On a practical level, squeezing offers opportunities to make interferometric measurements much more precise than would normally be allowed by quantum uncertainty limits.

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Putting the squeeze on phonons

Photon squeezing has been the subject of intense interest in the field of quantum optics, since it serves as a unique demonstration of the quantum nature of light. On a practical level, squeezing offers opportunities to make interferometric measurements much more precise than would normally be allowed by quantum uncertainty limits. In principle, the physics of squeezing may be applied to many different types of bosons.

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A fast selenium derivatization strategy for crystallization and phasing of nucleic acid structures

The growing number of biologically important nucleic acid sequences (DNA and RNA) demands a fast and reliable method for their de novo three-dimensional structure determination. In this work, we described a fast and inexpensive strategy for the crystallization and phasing of structures of nucleic acid and nucleic acid/protein complexes.

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Exciting Heavy Metal

Photocatalysts play an important role in a broad range of applications, from photochemical conversion of light energy into chemical energy through to initiating novel chemical reactions. One family of compounds that has attracted much attention is the dinuclear d8-d8 platinum, rhodium and iridium complexes that have a highly reactive electronic excited state.

Femtosecond molecular spin crossover

X-ray absorption spectroscopy is a powerful probe of molecular structure, but it has previously been too slow to track the earliest dynamics after photoexcitation. We investigated the ultrafast formation of the lowest quintet state of aqueous iron(II)tris(bipyridine) upon excitation of the singlet metal-to-ligand-charge-transfer (1MLCT) state by femtosecond optical pump/x-ray probe techniques based on x-ray absorption near-edge structure (XANES).