Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Capturing Those In-Between Moments: NIST Solves Timing Problem in Molecular Modeling

Colorized simulation of what happens to 1100 carbon atoms in a ‘flat’ sheet of graphene about 20 microseconds after the central atom is moved slightly upwards. Darker violet colors indicate atoms that have dropped below their original position, whereas the lighter green colors show where atoms have risen.

Credit: V.K. Tewary/NIST
Colorized simulation of what happens to 1100 carbon atoms in a ‘flat’ sheet of graphene about 20 microseconds after the central atom is moved slightly upwards. Darker violet colors indicate atoms that have dropped below their original position, whereas the lighter green colors show where atoms have risen. Credit: V.K. Tewary/NIST

Abstract:
A theoretical physicist at the National Institute of Standards and Technology (NIST) has developed a method for calculating the motions and forces of thousands of atoms simultaneously over a wider range of time scales than previously possible. The method overcomes a longstanding timing gap in modeling nanometer-scale materials and many other physical, chemical and biological systems at atomic and molecular levels.

Capturing Those In-Between Moments: NIST Solves Timing Problem in Molecular Modeling

Boulder, CO | Posted on November 16th, 2009

The new mathematical technique* can significantly improve modeling of atomic-scale processes that unfold over time, such as vibrations in a crystal. Conventional molecular dynamics (MD) techniques can accurately model processes that occur in increments measured in picoseconds to femtoseconds (trillionths to quadrillionths of a second). Other techniques can be used over longer periods to model bulk materials but not at the molecular level. The new NIST technique can access these longer time scales—in the critical range from nanoseconds to microseconds (billionths to millionths of a second)—at the molecular level. Scientists can now measure and understand what happens at key points in time that were not previously accessible, and throughout the full spectrum of time scales of interest in MD, says developer Vinod Tewary.

Modeling of material properties and physical processes is a valuable aid and supplement to theoretical and experimental studies, in part because experiments are very difficult at the nanoscale. MD calculations are usually based on the physics of individual atoms or molecules. This traditional approach is limited not only by time scale, but also by system size. It cannot be extended to processes involving thousands of atoms or more because today's computers—even supercomputers—cannot handle the billions of time steps required, Tewary says. By contrast, his new method incorporates a "Green's function," a mathematical approach that can calculate the condition of a very large system over flexible time scales in a single step. Thus, it overcomes the system size problem as well as the timing gap.

Tewary illustrated the new technique on two problems. He showed how a pulse propagating through a string of atoms, initiated by moving the middle atom, could be modeled for just a few femtoseconds with conventional MD, whereas the NIST method works for several microseconds. Tewary also calculated how ripples propagate in 1,100 carbon atoms in a sheet of graphene over periods up to about 45 microseconds, a problem that could not be solved previously. Normally thought of as a static flat sheet, the atoms in graphene actually must undulate somehow to remain stable, and the new technique shows how these ripples propagate. (See accompanying image and movie **). Consisting entirely of carbon atoms, graphene is a recently discovered honeycomb crystal material that may be an outstanding conductor for wires and other components in nanoscale electronics.

The new NIST technique is expected to enable modeling of many other processes that occur at time scales of nano- to microseconds, such as formation and growth of defects, conduction of heat, diffusion and radiation damage in materials. The technique could improve results in many different fields, from modeling of new nanotechnologies in the design stage to simulating the radiation damage from a "dirty bomb" over time.

NIST researchers plan to write a software program encoding the new technique to make it available to other users.

* V.K. Tewary. Extending time scale in molecular dynamics simulations: propagation of ripples in graphene. Physical Review B, Vol. 80, No. 16.. Published online Oct. 22, 2009.

Click http://www.nist.gov/public_affairs/techbeat/prb_gpn_wav_3d.avi to see a video clip (6.5 MB AVI file) that shows how ripples propagate in a sheet of graphene after the central atom is moved slightly upwards. The clip is a slow-motion version of action that occurs over about 45 microseconds.


####

About NIST
Founded in 1901, NIST is a non-regulatory federal agency within the U.S. Department of Commerce. NIST's mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.

For more information, please click here

Contacts:
Laura Ost

(301) 497-4880

Copyright © NIST

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

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Arrowhead Pharmaceuticals Files for Regulatory Clearance to Begin Phase 1/2 Study of ARC-521 April 28th, 2016

The Translational Research Center at the University Hospital of Erlangen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles such as exosomes April 28th, 2016

JPK reports on the use of a NanoWizard AFM system at the University of Kaiserslautern to study the interaction of bacteria with microstructured surfaces April 28th, 2016

Physics

Superfast light source made from artificial atom April 28th, 2016

The atom without properties April 22nd, 2016

Chemistry

Adding some salt to the recipe for energy storage materials: Researchers use common table salt as growth template April 22nd, 2016

NRL reveals novel uniform coating process of p-ALD April 21st, 2016

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

Possible Futures

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers April 28th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

Nanoelectronics

Exploring phosphorene, a promising new material April 29th, 2016

Physicists build 'electronic synapses' for neural networks April 21st, 2016

With simple process, UW-Madison engineers fabricate fastest flexible silicon transistor April 21st, 2016

All powered up: UCI chemists create battery technology with off-the-charts charging capacity April 21st, 2016

Materials/Metamaterials

Exploring phosphorene, a promising new material April 29th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

NREL finds nanotube semiconductors well-suited for PV systems April 27th, 2016

Atomic magnets using hydrogen and graphene April 27th, 2016

Announcements

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Arrowhead Pharmaceuticals Files for Regulatory Clearance to Begin Phase 1/2 Study of ARC-521 April 28th, 2016

The Translational Research Center at the University Hospital of Erlangen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles such as exosomes April 28th, 2016

Tools

Exploring phosphorene, a promising new material April 29th, 2016

JPK reports on the use of a NanoWizard AFM system at the University of Kaiserslautern to study the interaction of bacteria with microstructured surfaces April 28th, 2016

Chemists use DNA to build the world's tiniest thermometer April 27th, 2016

Bruker Introduces Dimension FastScan Pro Industrial AFM: Providing Nanometer-Resolution at High Scan Rates for up to 300-mm Samples April 26th, 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