|Helen Fielding is Professor of Physical Chemistry. Her research is focused on the spectroscopy and ultrafast dynamics of excited states of molecules and protein chromophores in the gas-phase and in solution. Before coming to UCL in 2003, she worked at King’s College London (Lecturer 1994-1997; Reader 1997-2002; Professor 2002-2003). Prior to this, she was a postdoctoral research fellow at the University of Amsterdam, working with Professors Ben van Linden van den Heuvell and Wim van der Zande (1993-1994), a scientist at the National Physical Laboratory (1992) and a DPhil student at Cambridge then Oxford, working with Professor Tim Softley (1989-1992).|
|Summary of research group|
|Professor Fielding’s group is recognized internationally for their original work in the field of spectroscopy and dynamics of excited state of molecules. During the last 15 years, they have designed and built four separate experiments employing photoelectron spectroscopy to study small neutral molecules in the gas-phase, large molecular anions in the gas-phase, molecules on surfaces and, most recently, organic chromophores in solution. They also have expertise in electronic structure theory to support the interpretation of their experimental work.They have a long-standing collaboration with Professor Graham Worth and current collaborations with Professor Jim Anderson, Professor Helen Hailes, Professor Geoff Thornton (UCL) and Professor Anastasia Bochenkova (Mosscow State University).|
Highlights from their work on biological chromophore anions include showing that the first electronically excited state of the isolated green fluorescent protein chromophore anion in the gas-phase is bound with respect to electron detachment, contradicting earlier theoretical predictions (J. Phys. Chem. A 116, 7943, 2012), finding that the relaxation dynamics in the gas-phase are identical to those in solution (Chem. Sci. 4, 921, 2013) and demonstrating that the redox properties of the chromophore can be controlled by moving the position of a hydroxy group on the chromophore or chemical substituents with electron withdrawing or electron donating character (Chem. Sci. 8, 1621, 2017; Chem. Sci. 8, 3154, 2017).
Another notable recent highlight was the first gas-phase study of the electronic structure and dynamics of a unidirectional molecular rotary motor; the motor was tagged with a carboxylic acid functional group so it could be transferred to the gas-phase using ESI Chem. Sci. 8, 6141, 2017. Not only did this provide important insight into the intrinsic dynamics of the molecular rotary motor, but it demonstrated the huge potential of anion photoelectron spectroscopy as a tool for studying the electronic structure and dynamics of molecular machines in the gas-phase and providing ideal benchmarks for theory.
In the last few years, the group has moved into the emerging field of liquid-microjet PES. Last year, they published the first comparison between gas-phase and aqueous solution-phase UV PES, of phenol, a ubiquitous molecular motif in large biologically relevant chromophores J. Phys. Chem. Lett. 9, 678-682 (2018).
A recent highlights from their work on femtosecond dynamics of isolated molecules in the gas-phase include the discovery of an entirely new non-radiative decay pathway in pyrrole dimers Nat. Commun. 7, 11357, 2016.
|Femtosecond and nanosecond laser systems, molecular beam velocity-map imaging photoelectron spectrometer, electrospray-ionisation velocity-map imaging anion photoelectron spectrometer, liquid-microjet bottle photoelectron spectrometer, UHV hemispherical photoelectron energy analyser.|