CO adsorption on CeO2(111): A CCSD(T) benchmark study using an embedded-cluster model.

Area of Science:

• Computational Chemistry
• Surface Science
• Materials Science

Background:

• Predicting molecular behavior on surfaces is crucial for catalysis and materials design.
• Accurate calculation of vibrational frequencies requires advanced computational methods.
• Cerium dioxide (CeO2) is an important material in catalysis, and understanding molecule adsorption is key.

Purpose of the Study:

• To present a benchmark computational model for predicting vibrational frequencies of molecules on ionic surfaces.
• To investigate the adsorption of carbon monoxide (CO) on the CeO2(111) surface.
• To accurately determine CO vibrational frequencies, including anharmonic effects.

Main Methods:

• Developed an embedded-cluster approach combined with wavefunction-based methods.
• Utilized second-order Møller-Plesset perturbation (MP2) and coupled-cluster singles and doubles with perturbational treatment of triple excitation (CCSD(T)) methods.
• Calculated CO harmonic and anharmonic vibrational frequencies and adsorption energies.

Main Results:

• Anharmonic effects were found to shift CO vibrational frequencies by approximately 25 cm-1.
• MP2 calculations underestimated harmonic frequencies compared to CCSD(T) results.
• The best estimate for the CO vibrational frequency on CeO2(111) was within 12 cm-1 of experimental values.
• Adsorption energy calculations indicated a physisorption character for CO on CeO2(111).

Conclusions:

• The benchmark model provides accurate predictions for molecular vibrational frequencies on surfaces.
• The study confirms the physisorption of CO on the CeO2(111) surface.
• The developed methodology can be applied to other molecule-surface systems.