Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Nanosensors could help determine tumors’ ability to remodel tissue: Measuring enzyme levels could help doctors select appropriate treatments September 29th, 2016

Innovation in Nanotechnology is Focus of Symposium: Annual event brings international experts to Northwestern Oct. 6 September 29th, 2016

Cambrios at CEATEC - Japan 2016 September 29th, 2016

Picosun patents ALD nanolaminate to prevent electronics from overheating September 28th, 2016

Possible Futures

Nanosensors could help determine tumors’ ability to remodel tissue: Measuring enzyme levels could help doctors select appropriate treatments September 29th, 2016

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Researchers at the Catalan Institute of Nanoscience and Nanotechnology show that bending semiconductors generates electricity September 26th, 2016

Chains of nanogold – forged with atomic precision September 23rd, 2016

Academic/Education

PHENOMEN is a FET-Open Research Project aiming to lay the foundations a new information technology September 19th, 2016

AIM Photonics Announces Release of Process Design Kit (PDK) for Integrated Silicon Photonics Design August 25th, 2016

Nanotech Security Featured by Simon Fraser University: Company's Anti-Counterfeiting Technology Developed With the Help of University's 4D LABS Materials Research Institute August 21st, 2016

W.M. Keck Foundation awards Cal State LA a $375,000 research and education grant August 4th, 2016

Discoveries

Nanosensors could help determine tumors’ ability to remodel tissue: Measuring enzyme levels could help doctors select appropriate treatments September 29th, 2016

Fighting cancer with sticky nanoparticles September 27th, 2016

Gold nanoparticles conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2 mediated pathway in breast cancer September 27th, 2016

UNAM develops successful nano edible coating which increases life food September 27th, 2016

Announcements

Nanosensors could help determine tumors’ ability to remodel tissue: Measuring enzyme levels could help doctors select appropriate treatments September 29th, 2016

Innovation in Nanotechnology is Focus of Symposium: Annual event brings international experts to Northwestern Oct. 6 September 29th, 2016

Cambrios at CEATEC - Japan 2016 September 29th, 2016

Picosun patents ALD nanolaminate to prevent electronics from overheating September 28th, 2016

Tools

Oxford Instruments systems now facilitate water purification technology September 27th, 2016

Dr Barbara Armbruster promoted to Worldwide Sales and Marketing Director for XEI Scientific September 27th, 2016

Oxford Instruments is ‘Bringing the Nanoworld Together’ in India once again - 22 - 23 November 2016 | IISc Bangalore September 21st, 2016

Bruker Introduces Complete Commercial AFM-Based SECM Solution: PeakForce SECM Mode Enables Previously Unobtainable Electrochemical Information September 20th, 2016

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