The prospect of studying the time evolution of matter at an atomic level, on the same timescale as bonds are made and broken, is extremely tantalising. Such knowledge is vital in our desire to better understand complex molecular systems. The techniques required to perform these experiments exist in York through spectroscopic studies and time-resolved electron diffraction. There will also be opportunities to get involved with collaborative projects in York and as far away as the Stanford Linear Accelerator Center (SLAC) in California.
This project will extend the use of the novel electron diffraction apparatus and perform complementary studies using time-resolved spectroscopy and diffraction and advanced computational methods. The electron diffraction experiments performed in York will have a time resolution of around 700 fs (limited by space-charge repulsion), and through collaborations at SLAC time resolution of better than 100 fs achieved by using the higher energy electrons). For both of these experiments we will be using ultrafast laser technology to produce short bunches of electrons, and utilising the same laser to photoinduce structural changes in a variety of molecular species that have industrial, medicinal, and astronomical relevance.
Our apparatus will be used to perform pump-probe experiments for various molecular species. As the experiments will be time resolved we will make use of ultrafast laser technology to produce short bunches of electrons, utilising the same laser to photoinduce structural changes such as trans-cis isomerisations in azobenzenes, species that could find uses as molecular switches.
The Wann group has a history of combining experimental techniques and quantum chemical methods to better understand real chemical problems in terms of their structures. This work takes that research to a new level by looking at the dynamic structures of molecular species rather than their static geometries.
A specific focus of the research will be on studying both nuclear and electronic structures in parallel to yield mechanisms of light switchable materials. Using the range of methods available we will be able to determine accurate structures for both long- and short-lived species and to probe links between changes in electronic structure and the changes in geometry. One example of the type of phenomenon that will be studied is the cis-trans photoisomerisation of E-cinnamonitrile, a highly topical molecule because spectroscopic signatures corresponding to its presence on Titan have been recorded by NASA’s Cassini probe during a recent fly-by. The isomerisation of E-cinnamonitrile is thought to lead to heterocyclic species such as quinoline in the dense clouds on Titan. There will also be opportunities to undertake research at the UK central facilities, the Rutherford Appleton Labs and Daresbury Labs, and to collaborate with overseas groups, particularly in Germany, New Zealand, and Canada.
Training will be provided in structural methods including electron diffraction, as well as in the use of femtosecond laser systems. Much of the work we perform requires simulation before and after experiment, and so the student will be trained in the use of software such as General Particle Tracer and SIMION, and in computational chemistry packages such as MolPro and Gaussian.
All Chemistry research students have access to our innovative Doctoral Training in Chemistry (iDTC): cohort-based training to support the development of scientific, transferable and employability skills: https://www.york.ac.uk/chemistry/postgraduate/idtc/
The Department of Chemistry holds an Athena SWAN Gold Award and is committed to supporting equality and diversity for all staff and students. The Department strives to provide a working environment which allows all staff and students to contribute fully, to flourish, and to excel: https://www.york.ac.uk/chemistry/ed/
. This PhD project is available to study full-time or part-time (50%).
This PhD will formally start on 1 October 2020. Induction activities will start on 28 September.