Electron attachment to CO2 embedded in superfluid He droplets.

Area of Science:

• Physical Chemistry
• Atomic and Molecular Physics
• Quantum Fluids

Background:

• Electron attachment to molecules is fundamental to understanding chemical reactions and material properties.
• Superfluid helium droplets provide unique, weakly interacting environments for studying molecular behavior.
• Previous studies on electron attachment to CO2 clusters show characteristic resonance features.

Purpose of the Study:

• Investigate electron attachment dynamics to CO2 molecules specifically embedded within superfluid helium droplets.
• Characterize the resulting ionic complexes and their formation pathways.
• Compare the observed resonance structures with those of pristine CO2 clusters to identify helium's influence.

Main Methods:

• Experimental study of electron attachment to CO2 molecules confined in superfluid helium droplets.
• Analysis of ionic complex formation, including (CO2)n(-) and (CO2)nO(-).
• Measurement of resonance contributions and their energy dependence up to 67 eV.

Main Results:

• Formation of non-decomposed (CO2)n(-) complexes via two resonance contributions at low energies (<5 eV).
• Observation of significantly different resonance shapes and positions compared to pristine CO2, indicating helium-mediated processes.
• Identification of resonances related to helium electronic excitation and subsequent anion formation, including nonstoichiometric (CO2)nO(-).

Conclusions:

• Superfluid helium droplets significantly alter electron attachment dynamics to CO2 compared to gas-phase or bulk clusters.
• Helium environment facilitates unique quenching and mediation processes, influencing anion formation pathways.
• The study reveals new insights into molecule-helium interactions and the formation of exotic ionic species.