NERC GW4+ DTP PhD Studentship: Atmospheric chemistry of radical and biradical intermediates

University of Bristol - Faculty of Science - School of Chemistry

The project:

Oxidation chemistry of volatile organic compounds in the Earth’s troposphere produces reactive radical and biradical species such as organo peroxy radicals and Criegee intermediates. Many of the reactions of these labile species are fast and can contribute significantly to the complex web of reactions leading ultimately to oxidized end-products such as CO2, H2O and H2SO4. The reactive radical intermediates may dominate the removal of persistent pollutants such as halogenated organic acids, and hence control their atmospheric lifetimes and fates. This project focuses on the reactions of Criegee intermediates (carbonyl oxides) and hydroxyalkyl peroxy radicals, which are produced by oxidation of both biogenic and anthropogenic alkenes in the atmosphere.

The Bristol group has developed a laser-based experiment to measure the rates of reactions of Criegee intermediates and hydroxyalkyl peroxy radicals with a variety of compounds. These reactions are expected to show unusual pressure and temperature dependences; for example, the barrierless reactions of Criegee intermediates with organic acids should become faster as the temperature decreases. The postgraduate student will measure reaction rates at temperatures down to 250 K and at pressures up to 1 atm to mimic the conditions found in the lower troposphere. She/he will measure rate coefficients for reactions of Criegee intermediates and hydroxyalkyl peroxy radicals with a variety of co-reagents, under dry conditions and with introduction of controlled vapour pressures of water. Reactions will include those of Criegee intermediates with several organic acids, and of hydroxyethyl peroxy radicals with HO2 and NO. Electronic structure calculations will guide the assignment of reaction products, and opportunities are expected to arise to spend time at the Advanced Light Source in California, working with Dr David Osborn and Dr Craig Taatjes (Sandia National Laboratory) to characterize the different reaction products using a unique vacuum UV ionization and mass spectrometry apparatus. The reaction rate coefficients and product channels will be incorporated into models of the chemistry of the troposphere to assess their impact on atmospheric composition and lifetimes.

How to apply:

Please make an online application for this project at http://www.bris.ac.uk/pg-howtoapply. Please select NERC Great Western Four Plus Doctoral Training Partnership PhD on the Programme Choice page and enter details of the studentship when prompted in the Funding and Research Details sections of the form.

Candidate requirements: First or Upper Second Class UK Honours degree, or the equivalent qualifications gained outside the UK. Applicants with a minimum Upper Second Class degree and significant relevant non-academic experience are encouraged to apply.

Funding: The majority of the studentships are available for applicants who are ordinarily resident in the UK and are classed as UK/EU for tuition fee purposes. A few fully funded studentships across the DTP are available for EU/EEA applicants not ordinarily resident in the UK (please note that this may be subject to change pending post EU referendum discussions). Applicants who are classed as International for tuition fee purposes are not eligible for funding.

Contacts: Prof. Andrew Orr-Ewing, email: a.orr-ewing@bristol.ac.uk. Contact number: 0117 9287672.

The University of Bristol is committed to equality and we value the diversity of our staff and students.

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Type / Role:

PhD

Location(s):

South West England