Subscribe free to our newsletters via your
. 24/7 Space News .




TECH SPACE
How many gold atoms make gold metal?
by Staff Writers
Helsinki, Finland (SPX) Apr 21, 2015


Nanogold is different from macroscopic gold. The small 102-gold atom cluster (right) behaves like a giant molecule, but slightly larger 144-gold atom cluster is like a metal. The image on the right is from ref. 1. Image courtesy The University of Jyvaskyla. For a larger version of this image please go here.

Researchers at the Nanoscience Center at the University of Jyvaskyla, Finland, have shown that dramatic changes in the electronic properties of nanometre-sized chunks of gold occur in well-defined size range. Small gold nanoclusters could be used, for instance, in short-term storage of energy or electric charge in the field of molecular electronics.

Funded by the Academy of Finland, the researchers have been able to obtain new information which is important, among other things, in developing bioimaging and sensing based on metal-like clusters.

Two recent papers by the researchers at Jyvaskyla (1, 2) demonstrate that the electronic properties of two different but still quite similar gold nanoclusters can be drastically different.

The clusters were synthesised by chemical methods incorporating a stabilising ligand layer on their surface. The researchers found that the smaller cluster, with up to 102 gold atoms, behaves like a giant molecule while the larger one, with at least 144 gold atoms, already behaves, in principle, like a macroscopic chunk of metal, but in nanosize.

The fundamentally different behaviour of these two differently sized gold nanoclusters was demonstrated by shining a laser light onto solution samples containing the clusters and by monitoring how energy dissipates from the clusters into the surrounding solvent.

"Molecules behave drastically different from metals," said Professor Mika Pettersson, the principal investigator of the team conducting the experiments.

"The additional energy from light, absorbed by the metal-like clusters, transfers to the environment extremely rapidly, in about one hundred billionth of a second, while a molecule-like cluster is excited to a higher energy state and dissipates the energy into the environment with a rate that is at least 100 times slower.

"This is exactly what we saw: the 102-gold atom cluster is a giant molecule showing even a transient magnetic state while the 144-gold atom cluster is already a metal. We've thus managed to bracket an important size region where this fundamentally interesting change in the behaviour takes place."

"These experimental results go together very well with what our team has seen from computational simulations on these systems," said Professor Hannu Hakkinen, a co-author of the studies and the scientific director of the nanoscience centre.

"My team predicted this kind of behaviour back in 2008-2009 when we saw big differences in the electronic structure of exactly these nanoclusters. It's wonderful that robust spectroscopic experiments have now proved these phenomena. In fact, the metal-like 144-atom cluster is even more interesting, since we just published a theoretical paper where we saw a big enhancement of the metallic properties of just a few copper atoms mixed with gold." (3)

The computational work was done at the CSC - the IT Center for Science in Espoo, Finland, and at the HLRS centre in Stuttgart, Germany.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Academy of Finland
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TECH SPACE
Scientists create invisible objects without metamaterial cloaking
Moscow, Russia (SPX) Apr 15, 2015
Physicists from ITMO University, Ioffe Institute and Australian National University managed to make homogenous cylindrical objects completely invisible in the microwave range. Contrary to the now prevailing notion of invisibility that relies on metamaterial coatings, the scientists achieved the result using a homogenous object without any additional coating layers. The method is based on a new u ... read more


TECH SPACE
A new view of the moon's formation

Moon formed when young Earth and little sister collided

Will the moon's first inhabitants live in giant lava tubes?

Soft Landing on the Moon an Extraordinary Challenge

TECH SPACE
Mars rover data boosts hope for liquid water on Mars

Examining Rock Outcrop at 'The Spirit of St. Louis' Crater

Mars has belts of glaciers consisting of frozen water

Mars' dust-covered glacial belts may contain tons of water

TECH SPACE
May I go to space once more asks Brian Duffy

Plants Use Sixth Sense for Growth Aboard the Space Station

How To Train Your Astronauts

Air Scrubber Plus Brings Space Age Technology Down To Earth

TECH SPACE
Chinese scientists mull power station in space

China completes second test on new carrier rocket's power system

China's Yutu rover reveals Moon's "complex" geological history

China's Space Laboratory Still Cloaked

TECH SPACE
Astronaut Hadfield to release first space album

Special 3-D delivery from space to Marshall Space Flight Center

NASA Extends Lockheed Martin Contract To Prepare Critical Cargo For ISS

NASA drives future discoveries with new ISS information system

TECH SPACE
Rocket tips over after SpaceX recycle attempt

SpaceX bid to recycle rocket fails again

RockSat-X Rescheduled for April 18

THOR 7 encapsulation as next Ariane 5 campaigns proceeds

TECH SPACE
Small solar eruptions can have profound effects on unprotected planets

The Solar System and Beyond is Awash in Water

Earthlike 'Star Wars' Tatooines may be common

Planets in the habitable zone around most stars, calculate researchers

TECH SPACE
Scientists create invisible objects without metamaterial cloaking

Radar-jamming decoy system completes testing

Solution-grown nanowires make the best lasers

Zuckerberg sees 'wild' future for virtual reality




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.