Scientists are using velocity-map imaging to examine inelastic scattering of hydroxyl radicals.
Hydroxyl radicals (OH) are important in many chemical systems, including combustion and atmospheric reactions. Measuring experimentally the speed and direction of travel of OH with specific forms of internal energy (e.g. rotational, vibrational and electronic energy) has proved difficult. However, measuring these aspects is a key diagnostic of the mechanism of the process that formed OH.
Now, these distributions (the state-to-state differential cross sections) for inelastic scattering of fully state-specified OH with He and Ar have been measured for the first time. This has been made possible by exploiting the velocity-map imaging technique in a crossed molecular-beam arrangement. The velocity-map imaging technique was invented at the Radboud University Nijmegen in 1997 by David Parker and coworkers.
The new article by David Parker and coworkers of the Institute for Molecules and Materials (IMM) can now be read online.
The measured speed and angular distributions are shown to compare favorably with theoretical predictions. This confirms the quality of calculated potential energy surfaces that are used to describe the astrochemically relevant collisions of OH with He.
- Gautam Sarma, Sarantos Marinakis, J. J. ter Meulen, David H. Parker, Kenneth G. McKendrick. Inelastic scattering of hydroxyl radicals with helium and argon by velocity-map imaging. Nature Chemistry, 2012; DOI: 10.1038/nchem.1480
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