Angling for gold: New model provides an alternative description of atomic level gold bonding

Sep 19, 2012
Angling for gold: New model provides an alternative description of atomic level gold bonding
Unravelling gold’s bonding mysteries. Credit: © Mike Boulden

(Phys.org)—A study on how gold atoms bond to other atoms using a model that takes into account bonds direction has been carried out by physicist Marie Backman from the University of Helsinki, Finland, and colleagues. These findings, which are about to be published in European Physical Journal B, are a first step toward better understanding how gold binds to other materials through strong, so-called covalent, bonds.

What scientists need is an empirical model, based on a so-called potential, that describes the gold-gold bond in a reliable way. Most previous models only accounted for interactions in the spherical around the atom. Although it is suitable to describe bonds between gold atom pairs, it is not adequate to describe how surface bond to other materials. In such a case, the density of interacting electrons is no longer spherical.

Indeed, bond angles matter when gold binds to other materials. Thus, the authors used a model based on potentials with angular dependence, referred to as Tersoff potential. It offers a compromise between including bond directionality, which is needed for covalent bonds, and keeping the computer time needed for the simulations low.

The authors used theoretical and to study gold atoms interacting with their neighbours. They fitted their potential functions to the most important observed characteristics of gold, such as gold atoms' lattice constant, binding energy and elastic constants. Thanks to such potential functions they were then able to describe bonding in atomistic simulations. This involves, first, determining the forces on each atom based on their relative positions and second solving equations of motion, to show how the atoms move, on a very short time scale.

Building on this model, future work could, for example, involve the development of cross potentials for and nanorods in a matrix, typically used in biomedical imaging and .

Explore further: New research predicts when, how materials will act

More information: M. Backman, N. Juslin, and K. Nordlund, Bond order potential for gold, European Physical Journal B 85:317, DOI 10.1140/epjb/e2012-30429-y

Related Stories

The finest gold dust in the world

May 30, 2012

(Phys.org) -- Scientists at the Vienna University of Technology found a method to locate single gold atoms on a surface. This should pave the way to better and cheaper catalysts.

Recommended for you

New filter could advance terahertz data transmission

Feb 27, 2015

University of Utah engineers have discovered a new approach for designing filters capable of separating different frequencies in the terahertz spectrum, the next generation of communications bandwidth that ...

The super-resolution revolution

Feb 27, 2015

Cambridge scientists are part of a resolution revolution. Building powerful instruments that shatter the physical limits of optical microscopy, they are beginning to watch molecular processes as they happen, ...

Precision gas sensor could fit on a chip

Feb 27, 2015

Using their expertise in silicon optics, Cornell engineers have miniaturized a light source in the elusive mid-infrared (mid-IR) spectrum, effectively squeezing the capabilities of a large, tabletop laser onto a 1-millimeter ...

A new X-ray microscope for nanoscale imaging

Feb 27, 2015

Delivering the capability to image nanostructures and chemical reactions down to nanometer resolution requires a new class of x-ray microscope that can perform precision microscopy experiments using ultra-bright ...

New research signals big future for quantum radar

Feb 26, 2015

A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

unknownorgin
not rated yet Sep 22, 2012
Some alloys of gold and copper are very resistant to most acids and micron size range particles of gold suspended in water will pass only blue light but reflect will a brown color. Gold alloyed with other metals can be green, red, siver or even pink depending on ratios.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.