A novel crossed-molecular-beam experiment for investigating reactions of state- and conformationally selected strong-field-seeking molecules

ABSTRACT

The structure and quantum state of the reactants have a profound impact on the kinetics and dynamics of chemical reactions. Over the past years, significant advances have been achieved in the control and manipulation of molecules with external electric and magnetic fields in molecular-beam experiments for investigations of their state-, structure- and energy-specific chemical reactivity. Whereas studies for neutrals have so far mainly focused on weak-field-seeking species, we report here progress towards investigating reactions of strong-field-seeking molecules by introducing a novel crossed-molecular-beam experiment featuring an electrostatic deflector. The new setup enables the characterisation of state- and geometry-specific effects in reactions under single-collision conditions. As a proof of principle, we present results on the chemi-ionisation reaction of metastable neon atoms with rotationally state-selected carbonyl sulfide (OCS) molecules and show that the branching ratio between the Penning and dissociative ionisation pathways strongly depends on the initial rotational state of OCS.

GRAPHICAL ABSTRACT

Keywords:

• Crossed-molecular-beam experiments
• state-selected reactions
• electrostatic deflection
• chemi-ionisation
• Penning ionisation

Acknowledgments

We acknowledge Philipp Knöpfel, Grischa Martin, Georg Holderied and Anatoly Johnson (University of Basel) for technical support. We also would like to thank Prof. Kopin Liu (IAMS Taipei) for valuable suggestions and fruitful discussions during the conception of the experimental setup. We thank Prof. Frank Stienkemeier (University of Freiburg) for providing us with a CRUCS valve used in the present experiments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is supported by Swiss National Science Foundation under [grant number BSCGI0_15787] and the University of Basel. H. G. and S. W. acknowledge support by the K. C. Wong Education Foundation.