X-ray Lasers Taking Pictures of Complex Molecules
by M. Arafat
Thursday 10th of March 2022
Science Daily - Kansas State University - Daniel Rolles and Artem Rudenko, along with their graduate student, Xiang Li, are part of an international team of researchers who have published an article called, "X-ray multiphoton-induced Coulomb complex complex single molecules", on Nature Physics , a monthly journal. publishing research in all areas of physics, clean and practical.
The team used the world's largest X-ray laser, the European XFEL, to capture complex molecules. With X-ray light, scientists were able to capture abridges of iodopyridine gas-phase molecules by atomic correction. In this process, the molecules are exploded by X-ray laser, and the image is reconstructed from fragments.
In a process known as Coulomb explosion imaging, high-intensity and ultra-short X-ray laser pulse emits large amounts of electrons in a molecule. Due to the strong electrostatic pressure between the remaining, well-charged atoms, the molecule explodes between a few femtoseconds - half a billion seconds, individual atoms disintegrate are detected by the detector.
“Our team and many other researchers have been conducting similar Coulomb research to photograph the explosion, but we have never been able to capture clear and precise images of such a large molecule this way before,” Rolles emphasized.
The work published in Nature Physics is part of a broader effort to develop this new method of photography, and one of the key points is that scientists can see all the hydrogen atoms, which are difficult to compare with conventional techniques such as X-ray or electron diffraction.
"Recently, our collaboration published a closely related paper in Physical Review Research, led by our graduate student, Xiang Li, in which we showed that in simple molecules, even a full 3D structure can be captured," said Rudenko.
Photographs are an important step in the recording of molecular films, which researchers hope to use in the future to capture the details of biochemical, chemical, and physiological reactions with high resolution.
This realization comes at a time especially as the SLAC National Lab at Stanford is about to launch its advanced X-ray laser with high frequency, LCLS-2 this fall, which will produce pulses 1,000 times per second than the current version used so far. Combining these extremely high repetition rates with the Coulomb explosive imagination promises to transform the molecular “filmmaking” field, which will benefit important technological areas such as solar energy conversion, photocatalysis and synthetic photosynthesis.
"We have just received more than $ 1.1 million in funding from the National Science Foundation to purchase a high-density replica, 100-kHz femtosecond laser at our laboratory here in K-State," said Rudenko. "With this new laser and the things we've learned about the Coulomb explosion, we hope we can capture similar movies here."
Rolles and Rudenko work for J.R. Macdonald Laboratory at the K-State physics department, which is one of the most active atomic, molecular and Optical physics centers in the United States. Like SLAC, the lab is funded by the U.S. Department of Energy. Li now works at the SLAC National Accelerator Laboratory.