Imaging Reactive and Inelastic Stereodynamics of Radicals
Lead Research Organisation:
Heriot-Watt University
Department Name: Sch of Engineering and Physical Science
Abstract
This is a PhD research project in Chemistry. The project will study the stereodynamics of collisions of small radical molecules, using a combination of crossed molecular beams with spectroscopic state detection through resonance-enhanced multiphoton-ionisation, coupled to velocity-map imaging of the resulting ions. The radicals (e.g. NO, OH, CH) will be collided with atoms and molecules of interest in atmospheric, combustion or astrochemical environments, and the candidate will determine the differential scattering cross sections for the radicals at a rotational state-specific level, and where possible, the angle-resolved rotational polarization moments. These results will be compared to theoretical models of the scattering, either classical, or where possible quantum mechanical, providing information on, and tests of, the potential energy surfaces that determine the collision dynamics.
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509474/1 | 01/10/2016 | 30/09/2021 | |||
| 1813045 | Studentship | EP/N509474/1 | 01/09/2016 | 29/02/2020 | Joseph Leng |
| Description | ABS Trust UK Bursary 2019 |
| Amount | £500 (GBP) |
| Organisation | Association of British Spectroscopists |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 07/2019 |
| End | 07/2019 |
| Description | RSC Travel Grant for PhD Students and Early Career Scientists |
| Amount | £800 (GBP) |
| Funding ID | T19-2165 |
| Organisation | Royal Society of Chemistry |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 06/2019 |
| End | 07/2019 |
| Description | Royal Commission for the Exhibition of 1851 Special Award |
| Amount | £300 (GBP) |
| Organisation | Royal Commission for the Exhibition of 1851 |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 04/2019 |
| End | 07/2019 |
| Description | Experiment - Dave Chandler |
| Organisation | Sandia Laboratories |
| Department | Combustion Research Facility |
| Country | United States |
| Sector | Public |
| PI Contribution | The PDRA, Dr T. R. Sharples, employed on the project visited the laboratory of Dr David Chandler at Sandia National Lab, Livermore for a 4 week period in Jan/Feb 2014. The primary aim of the visit was to learn about the technique of velocity-map imaging and in particular its application in minature crossed-molecular beam systems. Dr Sharples contributed to on-going experiments in Dr Chandler's laboratory during the visit. Dr Chandler has subsequently visited Heriot-Watt for 1 week (Sept 2016) during which we performed the first proof of concept measurements for a 4-vector correlation in inelastic rotational energy transfer, this lead to a publication in Nature Chemistry. |
| Collaborator Contribution | Dr David Chandler is a world-expert on the application of imaging techniques in molecular dynamics, having introduced the idea of ion-imaging itself in the 1980s. He is also an expert in crossed-molecular beam experiments, and designed the first miniature apparatus to include velocity-map imaging. Previous collaboration with him lead to the proof-of-concept publications that were instrumental in the funding of this project. In this particular collaboration, he has provided training for the PDRA in crossed-beam VMI techniques, and provided valuable technical insight into the design of the new apparatus at Heriot-Watt. |
| Impact | Steill et al. Journal of Physical Chemistry A, 117, 8163 (2013) Sharples et al. Journal of Chemical Physics 143 204301(2015) Luxford et al. Journal of Chemical Physics 145 084312 (2016) Luxford et al. Journal of Chemical Physics 145 174304 (2016) Luxford et al. Journal of Chemical Physics 147 013912 (2017) Sharples et al. Nature Chemistry 10 1148 (2018) |
| Start Year | 2013 |
| Description | QCT Calculations of Inelastic Scattering (Prof Javier Aoiz) |
| Organisation | Complutense University of Madrid |
| Country | Spain |
| Sector | Academic/University |
| PI Contribution | We have provided state-of-the-art experimental measurements of rotationally inelastic scattering of electronically excited NO radicals. Specifically for this collaboration, we made the first ever 4-vector stereodynamics measurements of the scattering angle dependence of rotational orientation transfer. We supported this with quantum scattering calculations on the literature potential energy surfaces. |
| Collaborator Contribution | Our collaborator (Prof Javier Aoiz) is a world expert in quasiclassical scattering calculations, in particular their application to the stereodynamics of reactive and inelastic collisions. He performed such calculations using the same literature potentials as used in our quantum scattering calculations. This enabled us to compare the ability of both classical and quantum calculations to reproduce our experimental results, thereby testing the importance of quantum interference effects in the observed scattering dynamics. The surprising result was that the classical calculations were qualitatively able to describe the scattering dynamics, indicating that interference effects were not responsible for the majority of the observed dynamics. However, more subtle effects were present in the quantum calculations, but not in the classical ones, indicating some influence from purely quantum effects. |
| Impact | 'Non-Intuitive Rotational Re-Orientation in collisions of NO(A) withe Ne form direct measurement of a four-vector correlation' published in Nature Chemistry vol. 10 page 1148 (2018). This on-going collaboration has been included in the successful award of a Programme grant from the EPSRC (EP/T021675/1). |
| Start Year | 2018 |