A simple quantum dynamics problem?

Jul 14, 2010
A simple quantum dynamics problem?
This is a step-by-step dissociation of Ne2Br2. Credit: American Institute of Physics

Research reported in The Journal of Chemical Physics, which is published by the American Institute of Physics, provides the first real-time measurements of the time dependence of the individual steps of dissociation of a complex consisting of two rare gas atoms and a halogen molecule.

"The goal of this work is to provide a test case for quantum dynamics theory," says author Kenneth C. Janda of the University of California, Irvine. "It is a problem that is easy, but not too easy, in the sense that a fundamental quantum dynamics explanation is within reach."

Researchers cooled a mixture of helium, neon, and bromine by spraying it through a nozzle, resulting in a stream of gas particles traveling at the same speed. This created a very low temperature in a moving frame of reference -- the particles were stationary relative to one another and condensed to form Ne2Br2 tetrahedral complexes. After the bromine molecule was excited with a laser pulse, the dissociation of the complex over a period of tens of picoseconds was observed spectroscopically.

Adding 16 quanta of vibrational energy to the bromine-stretching vibration resulted in rapid direct dissociation. The two Ne atoms dissociated without interacting with each other. However, with slightly higher vibrational excitation, a 23-quanta boost, the bromine anharmonicity led to sharing of the kinetic energy between the Ne atoms and a much more complicated dissociation mechanism.

"For 23 quanta, the first transfer of vibration fails to knock off one of the neon atoms 80 percent of the time," says Janda. "Instead a tiny liquid drop is formed, allowing a neon atom to move in a direct line with the bromine . The next vibration shoots it off like a pool stick hitting the cue ball."

Explore further: New filter could advance terahertz data transmission

More information: The article "Real-time dissociation dynamics of the Ne2Br2 van der Waals complex" by Jordan M. Pio, Molly A. Taylor, Wytze E. van der Veer, Craig R. Bieler, Jose A. Cabrera, and Kenneth C. Janda was published online in The Journal of Chemical Physics on July 7, 2010. See: link.aip.org/link/JCPSA6/v133/i1/p014305/s1

Provided by American Institute of Physics

4.6 /5 (14 votes)

Related Stories

How to split a water molecule

Apr 18, 2010

(PhysOrg.com) -- A research team at RIKEN, Japan’s flagship research organization has succeeded for the first time in selectively controlling for reaction products in the dissociation of a single water molecule ...

Cross-Dressing Rubidium May Reveal Clues for Exotic Computing

Feb 25, 2009

(PhysOrg.com) -- Neutral atoms--having no net electric charge--usually don't act very dramatically around a magnetic field. But by “dressing them up” with light, researchers at the Joint Quantum Institute, a collaborative ...

The Shapes of Molecules Really Matter for Heat Conduction

Sep 24, 2004

Too much heat can destroy a sturdy automobile engine or a miniature microchip. As scientists and engineers strive to make ever-smaller nanoscale devices, from molecular motors and switches to single-molecule transistors, ...

Satellites provide new insight into ozone-depleting species

Feb 25, 2009

Using data from the satellite-based MIPAS and GOME-2 instruments, scientists have for the first time detected important bromine species in the atmosphere. These new measurements will help scientists to better understand sources ...

Recommended for you

Breakthrough in OLED technology

11 hours ago

Organic light emitting diodes (OLEDs), which are made from carbon-containing materials, have the potential to revolutionize future display technologies, making low-power displays so thin they'll wrap or fold ...

Throwing light on a mysterious human 'superpower'

14 hours ago

Most people, at some point in their lives, have dreamt of being able to fly like Superman or develop superhuman strength like the Hulk. But very few know that we human beings have a "superpower" of our own, ...

New filter could advance terahertz data transmission

Feb 27, 2015

University of Utah engineers have discovered a new approach for designing filters capable of separating different frequencies in the terahertz spectrum, the next generation of communications bandwidth that ...

The super-resolution revolution

Feb 27, 2015

Cambridge scientists are part of a resolution revolution. Building powerful instruments that shatter the physical limits of optical microscopy, they are beginning to watch molecular processes as they happen, ...

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.