The stochastic wave function method for diffusion of alkali atoms on metallic surfaces

Area of Science:

• Surface Science
• Quantum Dynamics
• Condensed Matter Physics

Background:

• Understanding alkali atom diffusion on metallic surfaces is crucial for surface science and catalysis.
• Existing models often simplify complex quantum interactions, limiting predictive accuracy.
• The Caldeira-Leggett model provides a framework for studying quantum dissipation.

Purpose of the Study:

• To propose and validate a stochastic wave function method for studying alkali atom diffusion regimes on metallic surfaces.
• To characterize the surface diffusion dynamics of Na-Cu(111) and Li-Cu(111) systems.
• To compare numerical results with experimental data from helium spin-echo (HeSE) experiments.

Main Methods:

• Utilizing the Lindblad approach based on the microscopic Hamiltonian from the Caldeira-Leggett model.
• Performing numerical calculations of quantum dynamics for surface diffusion.
• Calculating the intermediate scattering function for isolated adsorbates.
• Comparing theoretical results with helium spin-echo (HeSE) experimental data.

Main Results:

• The stochastic wave function method successfully characterizes surface diffusion for Na-Cu(111) and Li-Cu(111).
• Numerical calculations quantitatively agree with HeSE experimental results in the Brownian limit.
• The 1-D quantum model (reduced dimensionality) effectively describes the experimental observations.
• The method's dependence on momentum transfer and temperature was illustrated.

Conclusions:

• The proposed stochastic wave function method offers a robust framework for studying quantum diffusion on surfaces.
• The 1-D quantum model provides a quantitatively accurate description of alkali atom diffusion dynamics.
• This approach bridges theoretical modeling and experimental validation in surface science.