In time with the molecules

(Nanowerk News) How do molecules change their shape when they chemically bond? How does matter change its structure when light is absorbed by atoms? Physicists, chemists and biologists have been dreaming for long time to directly watch the motion of atoms electrons after excitation with light. To realize such experiments in the future is also the merit of Professor Dr. Christian Spielmann from Friedrich Schiller University Jena (Germany). He is tenured professor at the Institute of Optics and Quantum Electronics. Together with his team they developed methods to generate ultra-short x-ray pulses on the laboratory scale which pave the way for observing the motion of atoms on their natural time scale.
Professor Spielmann will be awarded for his renowned work with the Thuringian Research Award 2010 in the category "basic research" on 1 April 2011. The award is worth 12,500 Euros. On the same occasion, two research teams from Jena and Hermsdorf will receive a prize in the category "applied research".
Prof Spielmann stated "it is a very special honour," and emphasizes that not only he himself but his whole team deserve this award. "I appreciate the recognition of our work, acknowledging the merit of our research in a very competitive environment."
Snapshots with the time-resolved x-ray spectroscopy
In order to be able to take "snapshots" of the motion of individual atoms, a measurement tool is required providing sufficiently high temporal and spatial resolution. "For this we use the time-resolved x-ray spectroscopy," explains research prize winner Spielmann. In order to capture the movements of atoms or molecules in an image without blurring, exposure times measured in femtoseconds are required: These are unimaginably short time periods - the millionth fraction of one billionth of a second.
In order to penetrate the microcosm of the building blocks of matter, the applied radiation used must have a short wavelength. "Already in the late 19th century, Ernst Abbe had shown the wavelengths of radiation must be comparable to the smallest features to be observed," says Prof. Spielmann. The exact position of atoms in molecules or solids cannot be captured by taking a picture with visible light. "However, with x-rays - which have a shorter wavelength than visible light - it is possible," says the physicist.
Science is currently pursuing two different strategies for the generation of intense ultrashort x-ray pulses. "On the one hand, large scale facilities are constructed, such as the x-ray laser at DESY in Hamburg," says the Jena physicist. Austrian-born Spielmann however, who has researched and taught at Jena University since 2008, is pursuing another approach: "We generate intense x-ray pulses on a small laboratory scale." The starting point is ultrashort laser pulse in the visible part of the spectrum. If the intense ultra-short laser pulse is focused in a gas jet, its wavelength is shifted towards shorter wavelengths. The shortest x-ray pulses can be generated efficiently using the methods optimized in recent years by Jena physicists.
The Thuringian Research Arward will be handed over on 1 April at 10 am in the Assembly Hall of Jena University (F├╝rstengraben 1, 07743 Jena).
Source: Friedrich Schiller University Jena