Formation and destruction of the OH- ion in ion-molecule reactions - experimental astrochemistry.

Advisor: Radek Plašil (DSPS FMF CUNI)

Funding: Fully funded


Negatively charged ions - anions - are present in various environments from planetary atmospheres to stellar photospheres to interstellar molecular clouds. Since the first astronomical discovery of an anion in 2006, the anion chemistry is a subject of intense experimental and theoretical research.

This work will focus on anion-molecule reactions that control the abundance of OH- in the interstellar environment. The experiments will utilize a radiofrequency ion trap with variable temperature from 10 to 300 K in conjunction with spectroscopic determination of OH- quantum states. We will study the formation, destruction, and isotopic substitution of OH- especially in the reactions of OH- with HD, H, CH4, and other species. The main result of the work will be the determination of the rate coefficients of the studied reactions in a broad range of temperatures below 300 K, where no experimental data are available. This information is important for astrochemical models and it may lead to a better understanding of the processes in the interstellar medium.


- T.J. Millar, C. Walsh, and T.A. Field, Negative Ions in Space, Chemical Reviews 117 (2017) 1765.
- Smith I.W.M., Low temperatures and cold molecules, Imperial College Press, London 2008, ISBN 978-1-84816-209-9.
- Ghosh P.K., Ion Traps, Clarendon Press, Oxford 1995, ISBN 978-0198539957.
- A.G.G.M. Tielens, The Molecular Universe, Rev. Mod. Phys. 85 (2013) 1021.
- Other scientific papers