Electron-induced fragmentation of water droplets: Simulation study

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Materials Science

Background:

• The behavior of free electrons in water is not fully understood.
• Electron-induced fragmentation of water clusters offers a novel approach to study this phenomenon.

Purpose of the Study:

• To develop and apply a computational protocol for simulating the fragmentation of water clusters upon electron impact ionization.
• To elucidate the mechanisms of electron-water interactions and fragmentation dynamics.

Main Methods:

• A composite protocol combining kinetic Monte Carlo for ionization events and classical molecular dynamics for fragmentation.
• Non-adiabatic quantum mechanics/molecular mechanics simulations to calibrate the ionization process.
• Simulation of various ionization pathways including single ionization, electronic excitation, elastic scattering, and autoionization via intermolecular Coulombic decay.

Main Results:

• Larger water clusters experience repeated ionization, leading to substantial fragmentation.
• Low-energy electrons contribute to fragmentation through electronic excitations after energy loss.
• The change in cluster size distribution serves as a sensitive indicator of energy transfer.

Conclusions:

• Simulating electron impact ionization and fragmentation provides valuable insights into electron transport in water.
• The developed computational protocol accurately models the complex fragmentation dynamics of water clusters.
• Cluster size distribution analysis is a powerful tool for quantifying energy transfer in electron-water interactions.