Oxygen adsorption on Mo(112) surface studied by ab initio genetic algorithm and experiment.

Area of Science:

• Surface Science
• Materials Science
• Computational Chemistry

Background:

• Oxygen adsorption on metal surfaces is crucial for catalysis and material properties.
• Understanding surface reconstructions is key to controlling material behavior.
• The Mo(112) surface is a model system for studying metal-oxygen interactions.

Purpose of the Study:

• To determine the atomic models of p(1x2) and p(1x3) surface structures on Mo(112) after oxygen adsorption.
• To investigate the stability and coexistence of different surface reconstructions under varying oxygen pressures.
• To elucidate the mechanism of oxygen-induced surface reconstruction on Mo(112).

Main Methods:

• Density functional theory (DFT) calculations.
• Genetic algorithm (GA) for structure prediction.
• Low energy electron diffraction (LEED).
• X-ray photoelectron spectroscopy (XPS).
• Scanning tunneling microscopy (STM).

Main Results:

• Simulations revealed unusual flexibility of the Mo(112) surface, leading to oxygen-induced reconstructions.
• More stable atomic models for p(1x2) and p(1x3) structures were identified compared to previous studies.
• Different p(1x2) and p(1x3) structures can coexist over a wide range of oxygen pressures.
• A pure p(1x2) structure is stable only within a narrow oxygen pressure range.
• A pure p(1x3) structure was found to be unstable under the studied conditions.

Conclusions:

• The Mo(112) surface exhibits significant reconstruction upon oxygen adsorption, driven by the metal's flexibility.
• The coexistence of various surface structures is pressure-dependent, with implications for surface reactivity.
• Computational findings are strongly supported by experimental data, validating the simulation approach.