Six-dimensional potential energy surface for H2 at Ru(0001)

Area of Science:

• Surface science
• Computational chemistry
• Physical chemistry

Background:

• Understanding molecule-surface interactions is crucial for catalysis.
• Accurate potential energy surfaces (PES) are essential for modeling surface reactions.
• Previous studies lacked a high-fidelity 6D PES for H(2)/Ru(0001).

Purpose of the Study:

• To compute the first accurate six-dimensional (6D) potential energy surface (PES) for H(2) interacting with a Ru(0001) surface.
• To compare the performance of two generalized gradient approximation (GGA) functionals (PW91 and RPBE) in describing this interaction.
• To construct an analytical PES for future dynamics studies.

Main Methods:

• Utilized density functional theory (DFT) with a pseudopotential-based periodic plane-wave approach.
• Employed two GGA exchange-correlation functionals: PW91 and RPBE.
• Constructed an analytical 6D PES using the corrugation reducing procedure based on DFT data.

Main Results:

• Achieved highly accurate interpolation of DFT/GGA data with minimal error (avg. 3 meV).
• Identified the top site as the most reactive for both PW91 and RPBE functionals.
• PW91 predicted higher reactivity and lower dissociation barriers compared to RPBE.
• Observed differences in energetic and geometric corrugation between the PW91 and RPBE PESs.

Conclusions:

• The developed analytical 6D PES provides a reliable representation of H(2)/Ru(0001) interactions.
• The choice of exchange-correlation functional significantly impacts the predicted reactivity and PES characteristics.
• Further comparison with experimental data is needed to validate the suitability of PW91 and RPBE for this system.