Water Attachment onto Size-Selected Cationic Pyrene Clusters

Area of Science:

• Physical Chemistry
• Astrochemistry
• Chemical Physics

Background:

• Understanding molecular interactions with nanoparticles is crucial for various fields, including astrochemistry.
• Pyrene clusters are relevant in astrophysical environments, and their interaction with water is not fully understood.

Purpose of the Study:

• To measure the attachment rates of water molecules onto cationic pyrene clusters.
• To determine the sticking coefficient of water on pyrene clusters.
• To model the attachment process and extrapolate findings to astrophysical conditions.

Main Methods:

• Mass-selected cationic pyrene clusters (n=4-13) were used.
• Attachment rates were measured at various collision energies.
• Collision-induced dissociation experiments were performed to determine collision rates.
• A model incorporating Langevin-type collision rates and statistical dissociation rates was developed.

Main Results:

• Attachment rates showed a strong dependence on pyrene cluster size and collision energy.
• Sticking coefficients were determined by comparing attachment and collision rates.
• The developed model successfully rationalized the experimental data.

Conclusions:

• The study provides quantitative data on water molecule attachment to pyrene clusters.
• The findings offer insights into the formation and evolution of icy species in astrophysical environments.
• The model allows extrapolation to conditions relevant for interstellar ice formation.