Krzysztof Szalewicz, professor of physics and astronomy at UD, was the principal investigator on the National Science Foundation funded research project, which solved equations of quantum mechanics to more precisely describe the interactions between molecules of hydrogen and carbon monoxide, the two most abundant gases in space.
Such calculations are important to spectroscopy, the science that identifies atoms or molecules by the color of light they absorb or emit. Sir Isaac Newton discovered that sunlight shining through a prism would separate into a rainbow of colors. Today, spectroscopy is essential to fields ranging from medical diagnostics to airport security.
In astrophysics, spectrometers attached to telescopes orbiting in space measure light across the visible, infrared, and microwave spectrum to detect and quantify the abundance of chemical elements and molecules, as well as their temperatures and densities, in places such as the vast Orion Nebula, a celestial maternity ward crowded with newborn stars, some 1,500 light years away.
Whereas carbon monoxide — the second-most abundant molecule in space — is easily detected by spectrometers, such is not the case for hydrogen. Despite ranking as the most abundant molecule in space, hydrogen emits and absorbs very little light in the spectral ranges that can be observed. Thus, researchers must deduce information about molecular hydrogen from its weak interactions with carbon monoxide in the interstellar medium (the stuff between the stars).
“The hydrogen spectra get lost on the way, but carbon monoxide is like a lighthouse — its spectra are observed more often than those of any other molecule,” Szalewicz says. “You can indirectly tell what the density of hydrogen is from the carbon monoxide spectra.”
Szalewicz and co-authors Piotr Jankowski, a former UD postdoctoral researcher who is now on the chemistry faculty at Nicolaus Copernicus University in Torun, Poland, and A. Robert W. McKellar, from the National Research Council in Ottawa, Canada, wanted to revisit the spectra of the hydrogen and carbon monoxide complex. The first time such a calculation was done was 14 years ago by Szalewicz and Jankowski, parallel to an accurate measurement by McKellar.
In their computational model, the scientists needed to determine first how electrons move around nuclei. To this end, they included simultaneous excitations of up to four electrons at a time. The energy levels produced by the rotations and vibrations of the nuclei then were computed and used to build a theoretical spectrum that could be compared with the measured one.
The team’s calculations, accomplished with the high-powered kolos computing cluster at UD, have resulted in theoretical spectra 100 times more accurate than those published 14 years ago. The theoretical and experimental spectra are now in near-perfect agreement, which allowed the team to “assign” the spectrum, that is, to determine how each spectral feature is related to the underlying motion of the nuclei, Szalewicz says.
The combined theoretical and experimental knowledge about this molecular complex now can be used to analyze recent results from satellite observatories to search for its direct spectral signal. Even more importantly, this knowledge can be used to get better information about the hydrogen molecule in space from indirect observations, Szalewicz notes.
“Spectroscopy provides the most precise information about matter that is available,” he says. “I am pleased that our computations have untangled such a complex problem.”
Szalewicz’s expertise is in numerically solving the equations for the motions of electrons resulting in molecules attracting or repelling each other and then using these interactions to look at different properties of clusters and condensed phases of matter.
His research has unveiled hidden properties of water and found a missing state in the beryllium dimer, both results previously reported in Science, and his findings about helium may lead to more accurate standards for measuring temperature and pressure.
Szalewicz was elected to the International Academy of Quantum Molecular Science in 2010 and is a fellow of the American Physical Society.
View the original story and images at http://www.udel.edu/udaily/2012/may/science-stars-053112.html
Andrea Boyle | Newswise Science News
Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie
Seeing the quantum future... literally
16.01.2017 | University of Sydney
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction