Statistical evaporation of rotating clusters. III. Molecular clusters

Area of Science:

• Physical Chemistry
• Chemical Physics
• Computational Chemistry

Background:

• Unimolecular evaporation is a fundamental process in molecular clusters.
• Statistical theories and molecular dynamics simulations offer complementary approaches to study this phenomenon.

Purpose of the Study:

• To develop and validate expressions for kinetic energy release and product angular momentum distributions in unimolecular evaporation using phase space theory (PST).
• To compare PST predictions with molecular dynamics simulations for various molecular cluster systems.

Main Methods:

• Application of phase space theory (PST) with sphere+sphere and sphere+linear rigid body assumptions.
• Investigation of interaction potential shapes and vibrational density of states anharmonicity within PST.
• Comparison of PST results with molecular dynamics simulations for nitrogen and methane clusters.

Main Results:

• Explicit expressions for kinetic energy released and product angular momentum distributions were derived using PST.
• Quantitative agreement was observed between PST predictions and molecular dynamics simulations for nitrogen and methane clusters.
• The accuracy of PST was confirmed across diverse systems and physical conditions.

Conclusions:

• Phase space theory (PST) provides an accurate framework for predicting statistical observables in unimolecular evaporation of weakly bound clusters.
• The study validates PST's utility in understanding the dynamics of molecular dissociation processes.
• The findings support the broader applicability of PST in chemical physics research.