Department Locally-Sensitive & Time-Resolved Spectroscopy
A complete characterisation of the molecular structure of matter in its natural or applied environment is prerequisite for an understanding of relevant bonding interactions, material properties, and physicochemical transformations. Through such characterisations, we aim to unravel reaction mechanisms and describe, and ideally drive improvement of, the performance of photoredox and photocatalytic functional materials. We achieve this by developing, applying, and offering access to highly-differential spectroscopic techniques that selectively probe microscopic behaviours in complex environments. These techniques allows us to interrogate the electronic and geometric structure of molecular ensembles and materials at specific locations and ideally map and even control the flow of charge, energy, and mass on the natural timescales that characterise physicochemical change.
We have a particular interest in liquid water, aqueous solutions, and aqueous interfaces within our department. Accordingly, we are applying our techniques and infrastructure to address diverse problems spanning aqueous-phase molecular reaction, environmentally-benign chemical and energy conversion, water purification, and biological radiation damage mechanisms.
The research in our department is sculpted around two main themes:
- The development and application of methods that characterise the steady-state electronic and nuclear geometric structure of novel material systems that can be used, for instance, to study the catalytic transformation of water or aqueous solutes in energy-efficient systems that produce solar fuels, store charge, or synthesise chemicals. This work is primarily performed using brilliant synchrotron light sources.
- The development and application of methods that probe the dynamic electronic and nuclear geometric structure of molecules and materials undergoing photoinduced chemical/physical changes and energy transfer processes on few-femtosecond to microsecond timescales. This work is performed at our ultrashort pulse laser facilities, being complemented by research using accelerator-based light sources. Here we have a specific focus on aqueous-phase processes.
Our department consists of three research groups:
To study the dynamic electronic structure of molecular ensembles and materials, we primarily utilise the femtosecond time-resolved, extreme ultraviolet photoelectron spectroscopy technique. This allows us to selectively study the interfacial properties of liquids and solids. We complement these experiments with ultrafast time-resolution linear and non-linear optical absorption-based techniques that allow interfacial and bulk properties of samples to be, respectively, discerned. More details about these experiments can be found at the Ultrafast Laser Laboratory for Applied Sciences (ULLAS) page.
To enhance on these capabilities, we are developing a state-of-the-art laser facility that will extend our ultrafast photoelectron and absorption spectroscopy experiments into the soft X-ray regime. This facility will combine few-femtosecond soft X-ray pulses with higher data acquisition rates, experimental time-resolution, and spatial selectivity. To achieve this, we have adopted and are developing next generation laser technologies along with bespoke X-ray generation and delivery infrastructure. Collectively, this work will enable condensed phase electronic structure investigations at the temporal and spatial limits of chemical change. For more details about these developments, see the Liquid & Interfacial Dynamics with Ultrafast X-rays (LIDUX) page.
To characterise the bulk and interfacial geometric structure of condensed matter and serve a broad international user community, we adopt and offer access to a range of spectromicroscopy techniques in combination with brilliant, diffraction limited synchrotron and laboratory-based infrared sources spanning the 0.1-300 THz (0.6-1000 meV) range. Associated end-stations enable Fourier-Transform spectroscopy, near-field spectromicroscopy, ellipsometry, and µs-time-resolved absorption spectroscopy studies of liquids, solids, surfaces, and thin films. More details about the infrared beamline, end-stations, laboratory facilities, and associated user service can be found at the InfraRed Initiative with Synchrotron-radiation (IRIS) group page.