Computational molecular science is a discipline where computational chemistry methods are employed to investigate atoms, molecules, molecular systems and nanoparticles regarding, for example, their shape, stability and color.

“The substance can be in gas, liquid or solid form, and interface layers are also interesting, such as the behavior of molecules or nanoparticles on various surfaces,” says Lauri Halonen.

He regards experimental research as a cornerstone for science, although for certain tasks, computational science is a better alternative. “Computational methods can be used to study systems that cannot be reached experimentally, or ones that are so complex that setting up experimental systems would be impractical and complicated to arrange. It helps tremendously to be able to use a calculation to predict whether setting up a test is worthwhile or whether a chemical reaction is possible or not. We could say that computational research has become an element that complements experimental research," Halonen explains.

Basic research to tackle everyday problems

The Centre of Excellence (CoE) for Computational Molecular Science (2006–2011) at the Kumpula Campus of the University of Helsinki has brought top specialist in the field together to intensify collaboration. The unit consists of five research groups that have a total of about 70 researchers at different career stages, from junior to senior scientists.

“We are applying the best computational methods available in the world to molecular research and, we are also doing experimental research,” says Halonen.

Part of the research is purely academic, but each group also tackles questions that deal with everyday life as well.

“For example, human eyesight is being investigated; an essential factor is the changing molecular structure depending on the type of light. In a task relating to a fusion reaction, we study heat-resistant materials that could be suitable for use inside a reaction chamber”, Halonen lists their research topics relating to practical applications, and continues: “Noble gas chemistry is associated with, for example, anesthetics. Gold nanoparticles have catalytic properties, i.e. they enhance chemical reactions, and the magnetic properties of molecular systems serve as a sensitive probe in the immediate surroundings of the molecules. In other words, they tell us about the molecular environment.”

Halonen’s own group is working to develop a new type of measuring technique to analyze a person’s breath when they exhale, and to determine issues relating to atmospheric energy.

Vibration driving doctoral theses

Elina Sälli is one of the 30 researchers working on their doctoral theses; she studies molecular vibration of molecules adsorbed on metal surfaces.

“In order to understand catalytic processes occurring on metal surfaces, it helps to know something about how molecules are adsorbed onto the surface and how molecular vibration changes in this situation. I have previously studied ammonium molecules on a nickel surface, and now I am studying it using other metal surfaces.”

A researcher describes molecular vibration with a mathematical model, and compares the model against experimental results. “The computational model approach is well suited for ammonia; it produces experimental results quite accurately,” says Sälli who works in Halonen’s group.

Teemu Salmi, another member of Halonen’s group, is also studying vibration frequencies. In his doctoral thesis, Salmi focuses on molecular complexes consisting of either two water molecules or a complex containing a water molecule and some other molecule. “I calculate how vibration frequencies change when a water molecule forms a complex.” The research topic is associated with atmospheric phenomena and identification of molecular complexes in the atmosphere.

Enriching interaction

Lauri Halonen’s perception of the current situation in computational molecular science is bright: “We are extremely well positioned to be doing this research in Finland. Here we have excellence in skills, and resourcing in computational science has been understood correctly.”

In spite of its name, the CoE conducts both computational and experimental science, and Halonen finds this a major strength. “Our work is also enriched by the interaction between classical mechanics and quantum mechanics, and by the fact that, thanks to Professor Pekka Pyykkö, our center hosts superior know how in quantum chemistry.”

The work is extremely international. Researchers at the CoE have collaboration partners in different parts of the world, as far as Australia and New Zealand. However, Europe is the key direction, especially due to the network projects funded by the EU.

"The researchers also move actively abroad, they participate in congresses giving presentations," Halonen explains and is happy to note that the traffic is also inbound.

In summer 2009, the CoE  arranged a highly esteemed congress of quantum chemistry, led by Professor Pyykkö, in Helsinki. Almost 700 participants came from more than 50 countries, and most of them were basic researchers in computational chemistry and physics. Similarly, the winter school of theoretical chemistry, held annually, attracts top researchers from all parts of the world.

Images, Top: “The Nobel Prize winning density functional theory is one reason why researchers are able to study biomolecules and other complex systems, but limits will be encountered at some point. What is to be done when the computational capacity is completely exhausted,” Lauri Halonen wonders. (c) Mari Hohtari, Rhinoceros Oy

Bottom: Department of Chemistry, Laboratory of Physical Chemistry. All of the researchers in the picture work in Lauri Halonen’s group. Left Jari Peltola, Teemu Salmi, Elina Sälli and Mikael Siltanen. c) Mari Hohtari, Rhinoceros Oy

Paula Böhling

Funding and computing capacity