Force Field Parameter Development for the Thiolate/Defective Au(111) Interface

Area of Science:

• Surface Science
• Nanotechnology
• Computational Chemistry

Background:

• Understanding self-assembled monolayers (SAMs) on gold surfaces is crucial for surface science and nanotechnology.
• Existing atomistic models struggle to accurately describe SAMs on reconstructed gold surfaces.

Purpose of the Study:

• To develop a novel atomistic force field model for alkanethiolate (AT) SAMs on reconstructed Au(111) surfaces.
• To accurately reproduce key features of AT SAMs, including vibrational spectra and torsion energy profiles.

Main Methods:

• Utilized periodic ab initio density functional theory (DFT) calculations to develop force field parameters.
• Trained force constants by matching vibrational spectra and torsion parameters by fitting DFT-derived torsion energy profiles.
• Validated the force field using classical molecular dynamics (MD) simulations of dodecanethiolate (C10S) SAMs on Au(111).

Main Results:

• The developed force field successfully reproduces key features of ethylthiolate (C2S) on Au(111).
• Classical MD simulations using the new force field showed good agreement with ab initio MD studies for Au-S interface models.
• Geometrical and structural properties of dodecanethiolate (C10S) SAMs were accurately predicted.

Conclusions:

• The new atomistic force field provides fundamental insights into AT SAMs on reconstructed Au(111) surfaces.
• This advancement enhances the existing knowledge base for interface research in nanotechnology.
• The model offers a reliable tool for future simulations and design of functionalized gold surfaces.