Reaction pathways for pyridine adsorption on silicon (0 0 1)

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Understanding pyridine chemisorption on silicon surfaces is crucial for surface science and materials engineering.
• Previous studies reported conflicting results regarding the dative to tight-bridge transition of pyridine on Si(001).

Purpose of the Study:

• To investigate the chemisorption of pyridine on the silicon (001) surface using Density Functional Theory (DFT).
• To determine accurate adsorption and activation energies for relevant surface structures.
• To clarify the dative to tight-bridge transition and the formation of inter-row chains.

Main Methods:

• Employing Density Functional Theory (DFT) calculations.
• Analyzing adsorption energies of six key structures.
• Calculating activation energies between these structures.
• Comparing four different DFT functionals, including range-separated hybrids with empirical dispersion.

Main Results:

• Reported adsorption and activation energies for pyridine on Si(001).
• Provided a detailed description of the dative to tight-bridge transition, resolving literature discrepancies.
• Explained the formation of inter-row chains observed in high-coverage experiments.
• Demonstrated that the DFT functional choice significantly impacts relative energetics.

Conclusions:

• The range-separated hybrid functional ωB97X-D, with empirical dispersion, offers the most consistent description of experimental data for pyridine chemisorption on Si(001).
• Accurate DFT functional selection is critical for reliable predictions in surface chemistry.
• This study clarifies key aspects of pyridine-silicon surface interactions.