Disentangling Competing Photochemical Reactions using Multi-Site X-ray Photoelectron Spectroscopy

Supervisory Team:   Dr Russell Minns

Project description

Time-resolved spectroscopy and scattering measurements (such as extreme ultraviolet photoelectron spectroscopy and ultrafast X-ray scattering) allow us to monitor the chemical changes occurring during a photochemical reaction. A key characteristic of the highlighted techniques is their ability to monitor all chemical structures, with no fundamental or technical limitations on what they can measure. This universal nature, however, comes with one significant drawback. The lack of selectivity in the probes means that all the information associated with the measured ensemble is often projected onto a single measurement axis (e.g. electron kinetic energy or scattering angle). In situations where a single reaction pathway dominates the photochemical process the information provided is rich and detailed. Photochemistry is however, seldom so simple and more generally involves the competition between multiple reaction pathways, particularly at deep UV pump energies. Differentiating the contributions of each pathway to the overall experimental signal is a fundamental challenge that often limits what we can learn from the retrieved experimental data. In many experiments, the signals from each pathway lead to overlapping features, limiting the resolution and making the unambiguous separation and identification of the individual contributions challenging. For more generally useful probes of complex photochemistry we need to balance the competing requirements of universality, such that it can monitor all intermediate states and geometries involved, and selectivity, such that each possible reaction pathway can be uniquely identified.

During this PhD you will explore the use of time-resolved X-ray photoelectron spectroscopy (TR-XPS) to achieve this demanding but game changing capability. XPS provides a localised view of the character around atomic sites within a molecule of interest. As competing reaction pathways can often be differentiated by localised changes around particular atoms TR-XPS will allow us to differentiate competing reaction pathways. To this end you will perform experiments at international Free Electron Laser facilities as part of an international team. You will take a leading role in the development, running and analysis of the experiments, presenting your results in journals and at national and international conferences.

If you wish to discuss any details of the project informally, please contact Dr Russell Minns, Email: [Email Address Removed].

Entry Requirements

A very good undergraduate degree (at least a UK 2:1 honours degree, or its international equivalent).

Closing date: applications should be received no later than 31 August 2021 for standard admissions, but later applications may be considered depending on the funds remaining in place.

Funding: For UK students, Tuition Fees and a stipend of £15,609 tax-free per annum for up to 3.5 years.

How To Apply

Applications should be made online. Select programme type (Research), 2021/22, Faculty of Physical Sciences and Engineering, next page select “PhD Chemistry (Full time)”. In Section 2 of the application form you should insert the name of the supervisor Dr Russell Minns

Applications should include:

Research Proposal

Curriculum Vitae

Two reference letters

Degree Transcripts to date

Apply online: https://www.southampton.ac.uk/courses/how-to-apply/postgraduate-applications.page

For further information please contact: [Email Address Removed]