Å·ÃÀAV

Biography

Professor Andrew Orr-Ewing CChem FÅ·ÃÀAV is the Leverhulme Chair of Physical Chemistry at the University of Bristol. He joined the School of Chemistry at the University of Bristol as the Royal Society Eliz. Challenor Research Fellow in 1994, and has since held numerous roles including head of physical and theoretical chemistry. Andrew obtained his BA, MA and DPhil from the University of Oxford (1984–1991), where he studied at Jesus College. His DPhil research in chemical reaction dynamics was supervised by Professor Gus Hancock. Andrew then spent two years as a postdoctoral researcher with Professor Richard N Zare at Stanford University before returning to the UK.
 
During his three decades of research and teaching at the University of Bristol, Andrew has mentored 55 postgraduate students and 33 postdoctoral research associates. Their work has resulted in almost 300 publications in peer-reviewed journals, in fields that include chemical reaction and photodissociation dynamics, molecular spectroscopy, atmospheric chemistry, trace-gas sensing, ultrafast photochemical dynamics, photoredox catalysis, and the optical properties of aerosols. 
 
Andrew was chair of the Å·ÃÀAV Spectroscopy and Dynamics Group from 2002–2008 and was a member of the Å·ÃÀAV’s Diversity Working Group from 2009–2013. He has been awarded several prizes by the Å·ÃÀAV: the Harrison Memorial Prize (1994); the Marlow Medal and Prize of the Faraday Division (1999); the Award in Optical Spectroscopy (2002); the Tilden Prize (2009); the Chemical Dynamics Award (2014); and the Faraday Lectureship Prize (2026). He is an elected Fellow of the Royal Society (2017), a Member of the Academia Europaea (2018), a Foreign Fellow of the National Academy of Sciences of India (2025) and an International Honorary Member of the American Academy of Arts and Sciences (2026). Since 2020, he has served as senior and executive editor of the Journal of Physical Chemistry A.

A diversity of backgrounds, experiences, and ideas enriches the research environment and promotes creativity.

Andrew Orr-Ewing

Q&A

Can you tell us more about your work?

The objective that underpins all of my research is to develop a deeper understanding of how chemical reactions happen. A unifying theme is the use of laser spectroscopy and other analytical methods to follow the progress of a reaction, ideally on timescales fast enough to resolve each step. In my doctoral and postdoctoral research, I focused on studying elementary reactions by extracting detailed mechanistic information from the vibrational and rotational motions of the participating molecules, and by comparing the laboratory measurements with computer simulations. During my independent career at Bristol, my interests have expanded to include using laser spectroscopy to study what happens to molecules that absorb ultraviolet or visible light (i.e., photochemistry), how this light-activated chemistry can catalyse chemical reactions (with the aspiration of making chemistry more sustainable), and how photochemical reactions affect the composition and properties of Earth’s atmosphere. My research laboratory now contains modern laser systems that can generate pulses of light short enough to take snapshots of some of the fastest processes that occur in chemistry, including breaking and making of chemical bonds. We are applying this technology to study how the molecules in small organic and aqueous aerosol particles present in the lower atmosphere are affected by exposure to sunlight, with implications for environmental pollution, air quality and the Earth’s climate. We are also exploring what happens to the latest generations of refrigerant and industrial foam-blowing gases when they escape to the atmosphere and are broken down by reaction with atmospheric oxidants. 
 
One of the many enjoyable aspects of academic research is the opportunity to explore new scientific directions. For example, the extraordinary capabilities now available with the advent of X-ray free electron lasers and ultrafast electron diffraction methods allow us to observe changes in the structures of molecules in real time during chemical reactions. Coming back to the types of question that first interested me as a DPhil student and postdoctoral researcher, I am now fortunate to be able to collaborate with groups in several countries who are using these methods to unravel the precise steps of chemical change on timescales of a trillionth of a second or less.

Who or what first sparked your interest in chemistry, and how has that interest evolved over time? 

In my first few years at secondary school, I was very fortunate to be taught chemistry by Mr Graham Hill (one of the authors of the Chemistry in Context textbook) who inspired my interest in the subject. Because I also enjoyed studying physics and mathematics, my interests from my undergraduate days onwards have mostly been in physical and theoretical chemistry, but I am always intrigued by how my research can be applied in other branches of chemistry. 

What has been the most rewarding or memorable highlight of your career so far? 

For me, there is no single, standout highlight. My whole career has been rewarding, and has developed through a combination of timely opportunities, good fortune, sound guidance (I have been lucky to have the support of several outstanding mentors), and the chance to work with numerous talented and motivated students and colleagues. 

What have been the biggest challenges that you have faced over the course of your time in science, and what have you learned from those experiences? 

As a researcher who needs access to high-tech and expensive equipment to carry out my research projects, a constant challenge is to secure the grants that fund my laboratory and support the people who can expertly use the equipment to its full potential. To write proposals that can attract this funding, I have learned that my research interests must keep evolving. On the plus side, these changes in focus encourage me to broaden my knowledge of other exciting areas of chemistry. 

Thinking back to earlier in your career, are there any words of wisdom that you wish someone had told you? 

I was fortunate to have various mentors at key stages in my career who offered me timely and wise guidance. An important part of my career development was to observe how they succeeded in balancing the many demands on their time, and I have become better at prioritising, and saying no to some requests. 

What impact would you say that your work is having on your field and/or the wider world? 

Most directly, I believe that my work is contributing to a deeper understanding of chemical reactivity, and that more broadly it is helping other scientists to explore current questions about the environment and climate. However, I recognise that this latter impact is indirect, and that my group’s efforts are just one part of a much larger global endeavour to address urgent challenges such as global heating. Perhaps the most important and tangible impact of my work is to help train the next generation(s) of scientifically literate people by equipping them with the skills to tackle these challenges in new and creative ways. 

What future directions or opportunities do you see for your work? 

I see many exciting new directions, some of which my group is already beginning to explore. We benefit from advances in laser technology, access to new national and international facilities, and extraordinary developments in computational and theoretical chemistry to push our research towards systems of ever-greater complexity. By exploiting these technological advances, physical chemists are steadily developing the capability to watch chemistry as it happens in real time. 

What do you wish more people understood about your field or the chemical sciences in general? 

I would like more people to understand that chemistry is all around us and impacts every part of our lives, from the energy that powers our devices to the air that we breathe, the foods we eat, the medicines that keep us healthy, and the materials that make up the objects we use every day. Chemistry also offers solutions to many of the global challenges that we currently face.

In what ways does creativity influence how you think about or carry out your work? 

Creativity is at the heart of all my research programmes. Without creativity, we would not be able to generate the ideas that allow us to secure the funding for people, equipment and chemicals needed to tackle exciting research questions. Creativity also brings novelty and excitement to my work every day because it generates new questions and innovative ways to answer these questions. 

Are there any scientific developments, either recent or on the horizon, that you are excited about? 

Many! I think we are in a golden age of scientific discovery. For example, the James Webb Space Telescope is capturing extraordinary images of our universe that are transforming our knowledge of planets beyond our solar system, using tools from molecular spectroscopy that are familiar to many chemists. With facilities like X-ray free electron lasers, we can now image chemical change at the molecular level. Modern computational chemistry can simulate this chemical change in ways I could never have imagined when I was a postgraduate student, and the pace at which it continues to develop is astonishing. 

What does good research culture mean to you, and why does it matter? 

To me, a good research culture is one in which everyone can contribute to their full potential. It is supportive and enabling, but it also encourages people to stretch themselves to develop new skills and understanding. A diversity of backgrounds, experiences, and ideas enriches the research environment and promotes creativity. This culture matters because researchers perform at their best when they feel they belong and are respected in their working environment, have the confidence to discuss their work with their colleagues, and have the time and resources to reflect deeply on their research problems. 

How can scientists try to improve the environmental sustainability of research? Can you give us any examples from your own experience or context? 

Our laboratories at the University of Bristol are all LEAF accredited, reflecting our efforts to improve their sustainability. However, we all recognise that the equipment and chemicals we use come with a significant environmental cost, as does our growing use of computers and artificial intelligence, and our travel worldwide to participate in conferences. In my own laboratory, as we replace older technologies with more efficient modern equipment, we lower the environmental impact of the day-to-day operation of the laboratory. We also endeavour to reduce our consumption of chemicals and solvents. Although the COVID-19 pandemic encouraged the use of video technology for conferences and seminars, the research community has largely reverted to in-person conference participation because it is more scientifically rewarding and facilitates new collaborations. 

How important would you say collaboration is for producing high quality science? How has collaboration influenced your work? 

In the fields I work in, collaboration is essential to produce new science that is at the forefront of current research. I especially enjoy collaborations that transform our understanding of our research data, or that lead my group into new research fields. Examples include my ongoing collaborations with computational chemists, atmospheric chemists, synthetic organic chemists, aerosol scientists, and materials chemists. It is important to keep an open mind about work from across discipline boundaries, and I certainly benefit from attending seminars and conference talks in areas that differ from my own specialisms. 

If you had unlimited resources, what research question would you most want to explore? 

I would like to explore ways to undo the environmental damage that we are doing to our planet on a scale that can truly make a difference. Objectives might be to develop methods to remove greenhouse and ozone-depleting gases from the atmosphere, or microplastics and PFAS from the global environment in safe and sustainable ways. But I fear that even with unlimited resources, this approach to solving problems that humans have created is now intractable.