Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New paper offers breakthrough on blinking molecules phenomenon

12.08.2010
A new paper by University of Notre Dame physicist Boldizsár Jankó and colleagues offers an important new understanding of an enduring mystery in chemical physics.

More than a century ago, at the dawn of modern quantum mechanics, the Noble Prize-winning physicist Neils Bohr predicted so-called "quantum jumps." He predicted that these jumps would be due to electrons making transitions between discrete energy levels of individual atoms and molecules.

Although controversial in Bohr's time, such quantum jumps were experimentally observed, and his prediction verified, in the 1980s. More recently, with the development of single molecule imaging techniques in the early 1990s, it has been possible to observe similar jumps in individual molecules.

Experimentally, these quantum jumps translate to discrete interruptions of the continuous emission from single molecules, revealing a phenomenon known as fluorescent intermittency or "blinking."

However, while certain instances of blinking can be directly ascribed to Bohr's original quantum jumps, many more cases exist where the observed fluorescence intermittency does not follow his predictions. Specifically, in systems as diverse as fluorescent proteins, single molecules and light harvesting complexes, single organic fluorophores, and, most recently, individual inorganic nanostructures, clear deviations from Bohr's predictions occur.

As a consequence, virtually all known fluorophores, including fluorescent quantum dots, rods and wires, exhibit unexplainable episodes of intermittent blinking in their emission.

The prevailing wisdom in the field of quantum mechanics was that the on and off blinking episodes were not correlated. However, at a 2007 conference on the phenomenon sponsored by Notre Dame's Institute for Theoretical Sciences, which Jankó directs, Fernando Stefani of the University of Buenos Aires presented research suggesting that there was, in fact, correlation between these on and off events. No theoretical model available at that time was able to explain these correlations.

In a 2008 Nature Physics paper, Jankó and a group of researchers that included Notre Dame chemistry professor Ken Kuno, physics visiting assistant professor Pavel Frantsuzov and Nobel Laureate Rudolph Marcus suggested that the on- and off-time intervals of intermittent nanocrystal quantum dots follow universal power law distributions. The discovery provided Jankó and other researchers in the field with the first hints for developing a deeper insight into the physical mechanism behind the vast range of on- and off-times in the intermittency.

In a new paper appearing in the journal Nano Letters, Jankó, Frantsuzov and Notre Dame graduate student Sándor Volkán-Kascó reveal that they have developed a model for the blinking phenomena that confirms what Stefani observed experimentally. The finding is important confirmation that strong correlation exists between the on and off phenomenon.

If the blinking process could be controlled, quantum dots could, for example, provide better, more stable imaging of cancer cells; provide researcher with real-time images of a viral infection, such as HIV, within a cell; lead to the development of a new generation of brighter display screens for computers, cell phones and other electronic applications; and even improved lighting fixtures for homes and offices.

The Nano Letters paper represents another important step in understanding the origins of the blinking phenomenon and identifying ways to control the process.

Boldizsar Janko | EurekAlert!
Further information:
http://www.nd.edu

Further reports about: Nano blinking cell phone quantum dot quantum mechanics single molecule

More articles from Physics and Astronomy:

nachricht New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>