Semiclassical multi-phonon theory for atom-surface scattering: Application to the Cu(111) system

Area of Science:

• Chemical Physics
• Surface Science
• Theoretical Chemistry

Background:

• Semiclassical perturbation theory is a key tool for understanding atom-surface interactions.
• Previous models often simplified phonon interactions, limiting accuracy at higher temperatures.

Purpose of the Study:

• To develop a more accurate theoretical model for atom-surface scattering.
• To incorporate full multi-phonon transitions into semiclassical perturbation theory.
• To improve agreement with experimental scattering data.

Main Methods:

• Extended the Hubbard-Miller semiclassical perturbation theory.
• Utilized a discretized bath of oscillators for multi-phonon transitions.
• Applied the theory to experimental data of Ne, Ar, and Kr scattered from Cu(111).

Main Results:

• Developed a practical expression for angular scattering distributions.
• Achieved good agreement with previous one- and two-phonon theories at low temperatures.
• Significantly improved agreement between theory and experiment at higher surface temperatures.

Conclusions:

• Multi-phonon transitions are crucial for accurately describing atom-surface scattering, particularly at elevated surface temperatures.
• The enhanced theory provides a more robust framework for analyzing experimental scattering data.
• This work validates the importance of considering complex phonon interactions in surface dynamics.