Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Physicists' findings about helium could lead to more accurate temperature, pressure measurements

Vial of glowing untrapure helium.  Image by Jurii
Vial of glowing untrapure helium. Image by Jurii

Abstract:
In the May 7 edition of Physical Review Letters, a journal of the American Physical Society, an international team led by University of Delaware researchers reports new findings about helium that may lead to more accurate standards for how temperature and pressure are measured.

by Tracey Bryant

Physicists' findings about helium could lead to more accurate temperature, pressure measurements

Newark, DE | Posted on May 19th, 2010

In the article, highlighted as an "Editor's Suggestion" by the journal, the scientists provide a new theoretical computation of the force acting between a pair of helium atoms, referred to as "pair potential," that is more accurate than any published to date.

Krzysztof Szalewicz, professor in the UD Department of Physics and Astronomy, led the study, which involved Wojciech Cencek, a postdoctoral researcher at UD, and colleagues from the University of Warsaw and Adam Mickiewicz University in Poland, and the University of Oslo in Norway.

Most of us know helium as a gas for filling party balloons or for making your voice temporarily sound like a cartoon character's. But this element named for the sun is used in lasers for eye surgery, to cooling agents in nuclear reactors.

Helium has a number of characteristics that make it special, Szalewicz says. It is the most stable of all the elements and has the lowest boiling point. It becomes a fluid at temperatures close to absolute zero while most other materials are a solid. In fact, helium is a liquid even at absolute zero and becomes a solid only at high pressure.

Helium is the only substance that exhibits superfluidity, and it will not burn or react with other elements, which is one reason why it is used as a pressurizing agent for liquid fuel rockets in space exploration, among many other applications.

"Of all the elements, helium is closest to the ideal gas," Szalewicz says. "Two helium atoms form the weakest bound diatomic molecule. All the properties of temperature, for example, which is a measure of the kinetic energy of particles in matter, can be modeled if the force acting between a pair of helium atoms is known.

"This has been the subject of extensive activity," Szalewicz notes, "as accurate knowledge of the pair potential of helium is of importance in several branches of science, including low-temperature condensed matter physics, spectroscopy, and metrology, which is the science of measurement."

The research team used complex numerical techniques to compute several physical effects in the helium pair potential which are rarely considered in molecular physics. These effects include couplings of the electronic and nuclear motions, contributions due to Einstein's special relativity, and the so-called quantum electrodynamics contributions due to the interaction of the electrons with the electromagnetic field.

The scientists predict that the binding energy of two molecules of helium, chemically referred to as a "dimer," is 6,790 times smaller than the potential depth, and the average separation between the atoms is 47 angstroms compared to the typical chemical bond length of about 1 angstrom. The estimated uncertainties of the theoretical results are an order of magnitude smaller than the best experimental ones, they report.

The thermophysical properties of gaseous helium computed from this potential now will be used to calibrate the apparatus for measuring properties such as viscosities or the speed of sound.

"These calculations should lead to new, better standards for quantities such as temperature or pressure," Szalewicz says. "Continuous improvement of metrology standards is important for progress in experimental science, as well as in many industrial applications."

The research was supported in part by grants from the National Institute of Standards and Technology and the National Science Foundation.

####

For more information, please click here

Contacts:
Phone: (302) 831-2792

Copyright © University of Delaware

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Multi-million pound project to use nanotechnology to improve safety September 4th, 2015

Magnetic wormhole connecting 2 regions of space created for the first time: The device could have applications in medicine, opening up ways to make MRIs more comfortable for patients September 4th, 2015

Tongfang Global and QD Vision Partner to Bring Wide Color Gamut to Global Television Lines: Color IQTM quantum dots help boost company’s focus on superior color reproduction September 3rd, 2015

QEOS and GLOBALFOUNDRIES to Offer Industry’s First CMOS Platform for MillimeterWave Markets: GLOBALSOLUTIONSSM Partnership will enable next-generation wireless technologies for applications in IoT, 5G and automotive September 3rd, 2015

Possible Futures

Magnetic wormhole connecting 2 regions of space created for the first time: The device could have applications in medicine, opening up ways to make MRIs more comfortable for patients September 4th, 2015

Silk bio-ink could help advance tissue engineering with 3-D printers September 2nd, 2015

Sediment dwelling creatures at risk from nanoparticles in common household products August 13th, 2015

Harris & Harris Group Reports Financial Statements as of June 30, 2015, and Announces a Stock Repurchase Program August 10th, 2015

Academic/Education

Sustainable nanotechnology center September 1st, 2015

National Science Foundation Selects SUNY Poly CNSE for Expanded $2.1M Northeast Advanced Technological Education Center: NSF Center Locates to NanoCollege in Support of Flourishing Tech Industry in NYS September 1st, 2015

Announcing Oxford Instruments and School of Physics signing a Memorandum of Understanding August 26th, 2015

Kwansei Gakuin University in Hyogo, Japan, uses Raman microscopy to study crystallographic defects in silicon carbide wafers August 25th, 2015

Discoveries

Magnetic wormhole connecting 2 regions of space created for the first time: The device could have applications in medicine, opening up ways to make MRIs more comfortable for patients September 4th, 2015

QEOS and GLOBALFOUNDRIES to Offer Industry’s First CMOS Platform for MillimeterWave Markets: GLOBALSOLUTIONSSM Partnership will enable next-generation wireless technologies for applications in IoT, 5G and automotive September 3rd, 2015

Making nanowires from protein and DNA September 3rd, 2015

Making fuel from light: Argonne research sheds light on photosynthesis and creation of solar fuel September 3rd, 2015

Announcements

Multi-million pound project to use nanotechnology to improve safety September 4th, 2015

Magnetic wormhole connecting 2 regions of space created for the first time: The device could have applications in medicine, opening up ways to make MRIs more comfortable for patients September 4th, 2015

Making nanowires from protein and DNA September 3rd, 2015

Making fuel from light: Argonne research sheds light on photosynthesis and creation of solar fuel September 3rd, 2015

Tools

Oxford Instruments’ Triton Cryofree dilution refrigerator selected by Oxford University for developing scalable quantum nanodevices September 2nd, 2015

JEOL Introduces New Best-in-Class Field Emission SEM September 2nd, 2015

Atomic Force Microscopes from Asylum Research Guide the Development of Thin Film Deposition and Etch Processes September 2nd, 2015

Nanolab Technologies LEAPS Forward with High-Performance Analysis Services to the World: Nanolab Orders Advanced Local Electrode Atom Probe (LEAP®) Microscope from CAMECA Unit of AMETEK Materials Analysis Division August 27th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic