Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Extremely cold molecules created by Sandia and Columbia University researchers

15.12.2003


Dave Chandler aligns mirrors used to direct laser beams into an apparatus that generates very cold molecules and measures their velocity.
Credit: Sandia Corporation


Colors of the ball indicate the number of molecules at a given velocity. The bright spot at the top of the image represents molecules moving with less than 15 M/Sec, with the intensity of the spot proportional to the number moving that slowly. The density of slow molecules is approximately 108 molecules per cm3.
Credit: Sandia Corporation


Using a method usually more suitable to billiards than atomic physics, researchers from Sandia National Laboratories and Columbia University have created extremely cold molecules that could be used as the first step in creating Bose-Einstein molecular condensates. The work is published in the Dec. 12 Science.

The serendipitous achievement came when researchers at Sandia’s Livermore, Calif., and Columbia University, studying collisional energy transfer between a beam of atoms intersecting a beam of molecules, noted that a certain number of collisions occurred -- as they might between two billiard balls -- at exactly the right velocity for molecules to become motionless.

A motionless molecule is a cold molecule, according to laws of physics.



The study had led to a new technique for cooling molecules to millikelvin (a thousandth of a degree Kelvin above absolute zero) temperatures -- a first crucial step toward molecular ultra-coldness.

Though they were experts in neither cold molecules nor cold atoms, the researchers knew that atoms cooled to the nanokelvin (a billionth of a degree Kelvin) temperature range had been achieved several years ago with interesting basic-science results.

One product of the study of cold atoms is a new state of matter called a Bose-Einstein condensate. Certain atoms, bosons, can condense at a very low temperature and act as a single atom -- a fact which some researchers claim may lead to as many new developments as the first laser, originally only a scientific curiousity.

"Our technique has promise to be developed into a first step in the cooling process needed for a molecular Bose-Einstein condensate," says Sandia researcher and principal investigator Dave Chandler. The work is co-authored by Sandia post-doc Mike Elioff and James Valentini of Columbia University.

Very cold atoms and molecules may one day be used as individual yes/no switches (called Q-bits) in computers whose power our present-day imaginations are only beginning to grasp as well as precision gravity detectors that could perhaps locate underground caverns, says Chandler.

The main method used to achieve atomic ultra-cooling to the microkelvin temperature range -- the same preliminary cooling range as the Sandia technique -- makes use of laser beams that intersect at a point. An atom, possessing the appropriate absorption characteristics, passing through that point in effect stands still, like a kid in a dodge-ball game struck from all sides with balls. Transfixed by pressure from the beams, the atom becomes almost motionless.

The problem in cooling molecules by the laser method is that while some atoms possess characteristics that can be harmonically matched by a laser frequency, like the same note played by two pianos, molecular energy frequencies are more complex. This complexity makes them unsuitable for this type of laser cooling.

This leaves the field open for other techniques to be developed for the preliminary cooling of molecules. There have been four or five other techniques, published recently, that have had some level of success at cooling molecules. The most successful method to date has been the welding of ultracold atoms together to make ultracold molecules.

"Our atomic/molecular beam intersection method is inefficient, it’s true," says Chandler. "We only manage to cool one molecule in a million. But -- inefficient or efficient -- we generate cold molecules. With some improvements, we hope to be able to make substantial numbers of cold molecules."

Molecules are cheap, he says, so getting one in a million (1 in 106) cooling collisions out of the 1015 total collisions per second the molecules undergo in the beams doesn’t bother him.

This first-step method -- the only one to rely solely on the masses of the atoms and molecules involved -- could be useful in slowing down the speed of a variety of molecules sufficiently such that magnetic or electrical traps can be used to cool molecules further. Without prior slow-down, molecules would escape these relatively weak traps, like molecules of water rising from the surface of the hot coffee. Cold coffee evaporates fewer molecules.

Instruments in Chandler’s lab, working at their resolution limit, show selected molecules in the intersecting beams slowing from 600 meters/sec to 15 meters/sec. The group’s calculations indicate the speed to be on the order of 4 meters/sec. This average speed for the molecules is equivalent to a temperature on the tens of milliKelvin level -- that is, several thousandths of a degree above the universe’s absolute zero of -273 Celsius.

The last ninety nine yards, so to speak, are the hardest: Bose-Einstein condensates exist in the nanokelvin range, six orders of magnitude colder.


The basic-science work, funded by DOE’s Basic Energy Sciences, focuses on understanding how energy flows between molecules for a better understanding of heat transfer.


Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

Sandia media contact:
Neal Singer, nsinger@sandia.gov, 505-845-7078

Neal Singer | Sandia Corporation
Further information:
http://www.sandia.gov/news-center/news-releases/2003/physics-astron/cold.html
http://www.sandia.gov

More articles from Physics and Astronomy:

nachricht NASA spacecraft investigate clues in radiation belts
28.03.2017 | NASA/Goddard Space Flight Center

nachricht Researchers create artificial materials atom-by-atom
28.03.2017 | Aalto University

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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>