The Ultrafast Belfast Research group uses state-of-the-art laser technology to study ultrafast molecular dynamics. We are part of the Centre for Plasma Physics, at Queen's University Belfast, in Northern Ireland.
We use femtosecond laser pulses to initiate and control molecular motion on ultrashort timescales. In our research we have imaged the motion of fundamental molecules, and demonstrated control over molecular fragmentation. Through new techniques using electrostatic ion traps, we are pursuing high-resolution studies of larger polyatomic molecules, with unique applications for research at the Life-Science interface.
13 August 2015
Ultrafast relaxation processes from first excited states in gas-phase nucleosides
The ultrafast photo-physical properties of DNA are crucial in providing a stable basis for life. The efficient internal conversion process, which converts the electronic energy in vibration energy to the surrounding environment, has been already observed in isolated bases. The present work, showing the first gas-phase measurements of electronic relaxation in DNA nucleosides, represents a natural next step in bottom-up understanding of DNA photo-physics.
The experimental lifetime of internal conversion to the ground state is observed to be shorter about half the lifetime of the relative bases, possibly due to an additional relaxation pathway mediated by proton transfer through a sugar to base hydrogen bond.
17 October 2014
Our Team Observes Electron Motion in a Biological Molecule on an Attosecond Timescale!
The work, reported in Science, was carried out using some of the shortest laser pulses in the world which were used as strobe lighting to track the ultrafast movement of the electrons within the nanometer-sized molecule. These attosecond laser pulses were used to initially stimulate the electrons and then to observe their resulting collective oscillations which lasted for 4300 attoseconds (billion-billionths of a second), the fastest process ever observed in a biological structure.
Explaining how electrons move on the nanoscale is crucial for the understanding of a range of processes in biology as it is this charge which initiates chemical reactions. For instance the charge produced from the interaction of ionizing radiation with DNA and its subsequent ultrafast excursions is crucial in determining the resulting damage to the DNA which can result in cell death or mutations. This knowledge is important for understanding the action of radiotherapy beams in cancer treatment.
Being able to describe how light interacts with electrons on these timescales could also lead to the technological improvements such as solar cells which collect electrons more efficiently or faster microprocessors which use light rather than electrical signals for switching transistors.
The attosecond laser used for the research was developed at the Politecnico di Milano as part of a long-standing collaboration between Professor Mauro Nisoli and Dr Francesca Calegari (IFN-CNR), and the study of electrons in biomolecules has since 2012 been the product of a collaboration with Ultrafast Belfast.