A six-dimensional potential energy surface for Ru(0001)(2×2):CO.

Area of Science:

• Surface Science
• Computational Chemistry
• Physical Chemistry

Background:

• Understanding molecule-surface interactions is crucial for catalysis.
• Carbon monoxide adsorption on metal surfaces like Ruthenium (Ru) is a fundamental system.
• Accurate potential energy surfaces (PES) are essential for modeling surface dynamics.

Purpose of the Study:

• To construct a new global ground state potential energy surface (PES) for carbon monoxide (CO) adsorbed on a rigid Ru(0001) surface.
• To accurately describe all six adsorbate degrees of freedom for CO on Ru(0001)(2×2):CO.
• To provide a reliable PES for future studies of CO dynamics and reactivity on metal surfaces.

Main Methods:

• Utilized over 90,000 density functional theory (DFT) points with the RPBE functional and van der Waals correction.
• Employed a symmetry-adapted corrugation reducing procedure (CRP) for interpolation.
• Solved the six-dimensional vibrational Schrödinger equation variationally to obtain anharmonic frequencies and wavefunctions.

Main Results:

• The constructed CRP PES identifies the atop position as the most stable adsorption site for CO on Ru(0001), with an adsorption energy of 1.69 eV.
• Surface diffusion is hindered by a barrier of 430 meV, and CO dissociation is facilitated but still activated.
• Calculated vibrational frequencies and wavefunctions show good agreement with experimental data.

Conclusions:

• The new CRP PES accurately represents CO adsorption and dynamics on Ru(0001).
• The analytical nature of the PES enables efficient multidimensional dynamics simulations.
• This work provides a valuable tool for understanding surface chemistry and catalysis.