Understanding how organic surfaces get dirty
Researchers have used Raijin to find new ways to understand how organic surfaces get dirty.
A combination of organic synthesis, scanning tunneling microscopy (STM) imaging, density functional theory calculations and access to the NCI’s supercomputing facility has led to this revelation.
The work is the result of an international collaboration between Professor Jeffrey Reimers and Associate Professor Mike Ford at the University of Technology Sydney, researchers at Shanghai University, the University of Sydney, the University of Melbourne and Radboud University in the Netherlands.
Professor Reimers says the paper, recently published in PNAS, focused on organic molecules sticking to graphite.
“State of the art chemistry and materials modelling based purely on the quantum interactions between nuclei and electrons hasn’t been able to treat organic surfaces before, as the interactions that cause things to stick are diffuse and involve many weak interactions between many atoms,” Professor Reimers explained.
“Such fundamental methods historically have poorly represented these weak interactions, and the system size has been too large.”
Professor Reimers said the graphite surface (akin to graphene) is highly ordered making both experimentation and computation much easier, allowing key properties of the interactions to be both measured and calculated.
“That our methods work for this simple testable situation implies they will also work for the other more structurally complex scenarios,” he said.
“Many people already model these other scenarios, especially in the polymer and drug design fields, and a lot of success has been achieved. We can do better now.”
Professor Reimers said that Raijin allowed the team to complete the computations quickly enough to make the work possible and that the human resources at NCI are just as important as the computational resources.
“NCI offers the advantage that it can do a lot of things at the same time, so you get things done when you need them rather than having to wait for months for the answer.
“Another advantage of NCI is that the staff and expertise are just as helpful as the compute power and facilities available to researchers.
“NCI differs from all other supercomputer facilities that I have dealt with in that the Help Desk staff really do help to get the work done.”
The team’s paper provides fundamental insight into the factors that control how and why the surfaces become dirty. It also demonstrates how to get critical information from traditional experiments, which Professor Reimers said can be applied to a large range of existing data.
“We have taken methods from the small-molecule arena and introduced them into the nanotechnology and biotechnology domains.
“There is still much to be done but related fields include the three dimensional structures of polymers, proteins and DNA, all of which are held together by the same widely distributed weak forces.”