• B.Sc. Hons (2011) Chemistry, University of Bristol, United Kingdom.
• Ph.D. (2015) Chemistry, University of Leeds, United Kingdom.
  • Thesis title: Low Temperature Kinetic Studies using a Pulsed Laval Nozzle Apparatus.
  • Thesis advisors: Prof. Dwayne E. Heard and Prof. John M. C. Plane.
• Postdoc (2015-2019) with Dr. Craig A. Taatjes, Sandia National Laboratories, CA, USA.
• NASA NPP postdoctoral fellow (2019) with Dr. Carl J. Percival, NASA Jet Propulsion Laboratory, California Institute of Technology, CA, USA.
• Assistant Chemist (2020-), Chemical Sciences and Engineering Division, Argonne National Laboratory.

Research interests

We are developing a state-of-the-art laser laboratory to study the kinetics and mechanisms of gas-phase reactions involving reactive intermediate species. Our experiments will interrogate the reactivity of zwitterions and radical intermediates to understand the role they play in as-yet unresolved phenomena, including gas-particle transformations in complex environments such as Earth’s troposphere. Our first setup (currently under development) is a broadband UV-Vis time-resolved absorption experiment that will enable kinetics and mechanistic studies using multiplexed species detection. Our table-top work at Argonne is complemented by ongoing work at DOE light sources, including the Advanced Light Source at Lawrence Berkeley National Laboratory, in collaboration with research teams from across the US and abroad.

Through collaborations with experimentalists and theorists in the Chemical Physics in the Gas Phase group and beyond, we will gain fundamental chemical physics insights into what drives and influences reactions of intermediates. Broader collaborations with, e.g., atmospheric scientists, will address the wider implications of our work, answering questions that are both interesting at a fundamental level and that have real-world implications.

Selected publications

Direct kinetic measurements and theoretical predictions of an isoprene-derived Criegee intermediate, Rebecca L. Caravan, Michael F. Vansco, Kendrew Au, M. Anwar H. Khan, Yu-Lin Li, Frank A. F. Winiberg, Kristen Zuraski, Yen-Hsiu Lin, Wen Chao, Nisalak Trongsiriwat, Patrick J. Walsh, David L. Osborn, Carl J. Percival, Jim Jr-Min Lin, Dudley E. Shallcross, Leonid Sheps, Stephen J. Klippnstein, Craig A. Taatjes & Marsha I. Lester, Proceedings of the National Academy of Sciences, 2020, DOI: 10.1073/pnas.1916711117.

The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol, Rebecca L. Caravan, M. Anwar H. Khan, Judit Zádor, Leonid Sheps, Ivan O. Antonov, Brandon Rotavera, Krupa Ramasesha, Kendrew Au, Ming-Wei Chen, Daniel Rösch, David L. Osborn, Christa Fittschen, Coralie Schoemaecker, Marius Duncianu, Asma Grira, Sebastien Dusasnter, Alexandre Tomas, Carl J. Percival, Dudley E. Shallcross & Craig A. Taatjes, Nature Communications, 2018, 9, 4343.

Criegee intermediates and their impacts on the troposphere, M. Anwar H. Khan, Carl J. Percival, Rebecca L. Caravan, Craig A. Taatjes & Dudley E. Shallcross, Environmental Science: Processes & Impacts, 2018, 20, 437-453.

Products of Criegee intermediate reactions with NO₂:experimental measurements and tropospheric implications,  Rebecca L. Caravan, M. Anwar H. Khan, Brandon Rotavera, Ewa Papajak, Ivan O. Antonov, Ming-Wei Chen, Kendrew Au, Wen Chao, David L. Osborn, Jim Jr-Min Lin, Carl J. Percival, Dudley E. Shallcross & Craig A. Taatjes, Faraday Discussions, 2017, 200, 313-330.

A combined experimental and theoretical study of reactions between the hydroxyl radical and oxygenated hydrocarbons relevant to astrochemical environments, Robin J. Shannon, Rebecca L. Caravan, Mark A. Blitz & Dwayne E. Heard, Physical Chemistry Chemical Physics, 2014, 16, 3466-3478.