Adsorption dynamics of polyatomic molecules on planar surfaces

Area of Science:

• Surface science
• Physical chemistry
• Computational physics

Background:

• Understanding gas adsorption dynamics is crucial for surface science and materials.
• Polyatomic molecules exhibit complex adsorption behaviors influenced by molecular size and orientation.
• Previous models often simplify gas-surface interactions, limiting their applicability to complex molecules.

Purpose of the Study:

• To comparatively study the adsorption dynamics of polyatomic molecules with increasing chain length on a planar surface.
• To elucidate the molecular mechanisms and key parameters governing gas uptake and film evolution.
• To develop an analytical model explaining adsorption dynamics, incorporating gas-gas interactions and molecular orientation.

Main Methods:

• Kinetic Monte Carlo (KMC) simulations were employed to model gas uptake.
• An analytical model was developed for monoatomic gas adsorption dynamics.
• The model was extended to account for the orientational freedom of polyatomic molecules.

Main Results:

• Simulations revealed molecular mechanisms governing the evolution of adsorbed films.
• The analytical model demonstrated a correlation between gas-gas interaction strength and adsorption rate dependence on coverage.
• The combined model successfully explained experimental observations of changing adsorption rates for longer molecules.

Conclusions:

• Adsorption dynamics are significantly influenced by molecular length, gas-gas interactions, and orientational freedom.
• The developed analytical framework provides a more comprehensive understanding of polyatomic molecule adsorption.
• This work offers insights into controlling gas uptake and film formation on surfaces.