Driving photochemistry by clustering: the ICl-Xe case

Area of Science:

• Physical Chemistry
• Chemical Physics
• Molecular Dynamics

Background:

• Understanding photodissociation dynamics is crucial for chemical reaction mechanisms.
• The influence of clustering on molecular fragmentation is not fully understood.

Purpose of the Study:

• To investigate the effect of clustering on the photodissociation dynamics of iodine monochloride (ICl).
• To probe the kinetic energy and angular distributions of chlorine (Cl) and iodine (I) photofragments.

Main Methods:

• Slice imaging data acquisition.
• Photodissociation of ICl at 235 nm in helium (He) and xenon (Xe) seed gasses.
• Analysis of fragment energy and angular distributions.

Main Results:

• Kinetic energy releases of Cl and I fragments were significantly altered by Xe seeding compared to He.
• Xe seeding resulted in broader kinetic energy distributions for Cl fragments and a dramatic shift from sharp features to broad distributions for I fragments.
• Observed changes were rationalized by a cluster model involving ICl dissociation within Xe clusters and on Xe surfaces.

Conclusions:

• Clustering, particularly with heavier gases like Xe, profoundly impacts molecular photodissociation pathways.
• The study provides evidence for cluster-specific effects on photofragmentation dynamics.
• A qualitative cluster model effectively explains the observed alterations in fragment energy distributions.