Since the trend of consolidation is and has historically been upward, fewer and fewer individuals or organizations control increasing shares of the mass media in our country. Media ownership in Australia is one of the most concentrated in the world ( Learn more). We don't put up a paywall – we believe in free access to information of public interest. Well, unlike many news organisations, we have no sponsors, no corporate or ideological interests. "We expect that this will extend not only the application of these techniques but also our theoretical understanding of the techniques themselves," says Takaba. The team intends to continue to explore how specimens interact with different probes. Importantly, no special sample preparation was needed for either method, making them practical to perform. Specifically, XFEL could determine atomic coordinates more accurately, whereas electron diffraction was more sensitive to the distribution of electric charges in the molecule. "XFEL and electron crystallography can reveal different and detailed features of organic compounds," says Maki-Yonekura. While the molecular structures obtained by the two techniques were very similar to each other, they also provided complimentary information since electrons and x-rays interacted differently with the samples. "It is an important achievement because the position of a hydrogen atom reveals the polarity of chemical bonds and because hydrogen atoms can significantly affect an organic molecule's properties and functions." ![]() "This is the first time anyone has demonstrated that hydrogen atoms in small crystals of organic compounds can be visualized by XFEL diffraction," notes Takaba. The positions of the hydrogen atoms resolved by the two techniques depended on the type of bonds between hydrogen atoms. Using both techniques, the researchers were able to resolve the positions of some of the hydrogen atoms, which is remarkable since they are the smallest atom, consisting of just a proton and electron. They also compared the results with those obtained using 3D electron diffraction for the same molecule. Now, Kiyofumi Takaba, Saori Maki-Yonekura, Yonekura and co-workers have used x-rays from an XFEL to determine the structure of a small organic molecule, a fluorescent dye called rhodamine-6G. Switching from x-rays to electrons can allow the structures of smaller crystals to be determined, but it has the downside that it requires very thin samples.Īnother promising approach is to use the ultra-intense, ultrashort x-ray pulses produced by x-ray free electron lasers (XFELs)-large facilities that are kilometers long. "Because many compounds cannot be obtained in large crystals, the ability to analyze the structures of small crystals is important in fields such as synthetic organic chemistry, pharmaceutical science and materials science," says Koji Yonekura of the RIKEN SPring-8 Center. However, many materials form crystals that are too small to be analyzed by x-ray diffraction. Many areas, including drug discovery and materials research, stand to benefit from this demonstration.Įver since William Lawrence Bragg and his father William Henry Bragg demonstrated that x-rays scattered from crystals produce distinctive patterns 110 years ago, x-ray diffraction has been the technique of choice for determining the structure of crystalline materials. The micrograph shows a field of crystalline particles outlined by a large selection aperture (6 µm at the specimen).Extremely intense x-ray pulses can determine the positions of some hydrogen atoms in organic molecules that form small crystals, an all-RIKEN team has shown 1. The figure above is electron diffraction patterns from selected small areas. ![]() Metals tend to give very strong electron diffraction patterns, whereas biological specimens generally diffract quite weakly. \), whereĮlectron diffraction provides a basis for studying the structure of crystals and of identifying materials.
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