Featured Research

from universities, journals, and other organizations

Capturing Those In-between Moments: Timing Problem In Molecular Modeling Solved

Date:
November 7, 2009
Source:
National Institute of Standards and Technology (NIST)
Summary:
A theoretical physicist 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.

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

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.

Related Articles


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. 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.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. V. K. Tewary. Extending the time scale in molecular dynamics simulations: Propagation of ripples in graphene. Physical Review B, 2009; 80 (16): 161409 DOI: 10.1103/PhysRevB.80.161409

Cite This Page:

National Institute of Standards and Technology (NIST). "Capturing Those In-between Moments: Timing Problem In Molecular Modeling Solved." ScienceDaily. ScienceDaily, 7 November 2009. <www.sciencedaily.com/releases/2009/11/091104111737.htm>.
National Institute of Standards and Technology (NIST). (2009, November 7). Capturing Those In-between Moments: Timing Problem In Molecular Modeling Solved. ScienceDaily. Retrieved April 25, 2015 from www.sciencedaily.com/releases/2009/11/091104111737.htm
National Institute of Standards and Technology (NIST). "Capturing Those In-between Moments: Timing Problem In Molecular Modeling Solved." ScienceDaily. www.sciencedaily.com/releases/2009/11/091104111737.htm (accessed April 25, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, April 25, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MINI Shows Off Augmented Reality Glasses

MINI Shows Off Augmented Reality Glasses

AP (Apr. 24, 2015) — MINI showcased its new augmented reality glasses at the Shanghai Auto Show this week, which designers say will make roads safer and allow the driver to see through opaque parts of the car. (April 24) Video provided by AP
Powered by NewsLook.com
3D Food Printing: The Meal of the Future?

3D Food Printing: The Meal of the Future?

AP (Apr. 23, 2015) — Developers of 3D food printing hope the culinary technology will revolutionize the way we cook and eat. (April 23) Video provided by AP
Powered by NewsLook.com
'Safest Bike Ever' Devised by British Entrepreneur

'Safest Bike Ever' Devised by British Entrepreneur

Reuters - Innovations Video Online (Apr. 23, 2015) — A British inventor says his Babel bike is the safest bicycle ever produced. Crispin Sinclair - son of famous British inventor Sir Clive Sinclair - hopes the bike&apos;s safety cage, double seatbelt, and host of other measures will inspire non-cyclists to get in the saddle. Jim Drury went to see it in action. Video provided by Reuters
Powered by NewsLook.com
First Successful Aerial Refueling of a Drone

First Successful Aerial Refueling of a Drone

Reuters - Innovations Video Online (Apr. 23, 2015) — The bat-wing U.S. Navy drone that became the first autonomous airplane to take off and land on an aircraft carrier accomplished yet another milestone on Wednesday, becoming the first unmanned aircraft to undergo aerial refueling. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins