New light cast on key chemical reactions in interstellar space

Jul 11, 2007

A detailed understanding of key chemical reactions that take place in interstellar space has been provided by groundbreaking research at two U.S. Department of Energy national laboratories and two European universities.

Argonne National Laboratory senior chemist Stephen Klippenstein – along with colleagues at Sandia National Laboratories; the Institute of Physics, University of Rennes, France; and the University of Cambridge, U.K. – has developed a detailed understanding of the dynamics of reactions between neutral radicals and neutral molecules, known as “neutral-neutral” reactions, at temperatures as low as 20 Kelvin, approximately the temperature of interstellar space.

In their work, Klippenstein and his collaborators determined why certain molecules reacted rapidly even at low temperatures by carefully comparing theory and experiment for a sample class of reactions (O3P + alkenes) that spans the range from non-reactive to highly reactive. The observed results from the experiment closely correlated with theoretical predictions, said Klippenstein.

“It was remarkable," he said, "just how well theory and experiment agreed throughout the whole spectrum from 20 Kelvin to room temperature. This means that we can rely on theory to predict which reactions will happen quickly.”

Establishing a working model for interstellar chemistry is especially important given the difficulty of performing large-scale experiments, according to Klippenstein.

“My collaborators have developed some great experimental techniques for measuring these reactions at low temperatures," he said. "But such experiments are still very time-consuming and are also hard to apply to many reactions. So schemes for predicting the reactivity for arbitrary reactions, either a priori or from extrapolation of measurements at higher temperatures, are of great utility to modelers of interstellar chemistry.”

Prior experimental studies with the CRESU (Reaction Kinetics in Uniform Supersonic Flow) technique demonstrated that a “surprising number” of neutral-neutral reactions remain rapid at very low temperatures. As a result, such reactions can play an important role in the chemistry of interstellar space, in contrast with the conventional wisdom that interstellar chemistry is essentially all ion-based.

The paper, entitled “Understanding Reactivity at Very Low Temperatures: The Reactions of Oxygen Atoms with Alkenes,” appears in the July 6 issue of Science.

Source: Argonne National Laboratory

Explore further: Used MRI magnets get a second chance at life in high-energy physics experiments

Related Stories

Water was plentiful in the early universe

May 13, 2015

Astronomers have long held that water—two hydrogen atoms and an oxygen atom—was a relative latecomer to the universe. They believed that any element heavier than helium had to have been formed in the ...

"Mini supernova" explosion could have big impact

Mar 16, 2015

In Hollywood blockbusters, explosions are often among the stars of the show. In space, explosions of actual stars are a focus for scientists who hope to better understand their births, lives, and deaths and ...

Recommended for you

SLAC gears up for dark matter hunt with LUX-ZEPLIN

May 21, 2015

Researchers have come a step closer to building one of the world's best dark matter detectors: The U.S. Department of Energy (DOE) recently signed off on the conceptual design of the proposed LUX-ZEPLIN (LZ) ...

First images of LHC collisions at 13 TeV

May 21, 2015

Last night, protons collided in the Large Hadron Collider (LHC) at the record-breaking energy of 13 TeV for the first time. These test collisions were to set up systems that protect the machine and detectors ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.