Water dissociating on rigid Ni(100): A quantum dynamics study on a full-dimensional potential energy surface

Area of Science:

• Surface Science
• Computational Chemistry
• Physical Chemistry

Background:

• Understanding gas-surface reactions is vital for catalysis and materials science.
• Accurate potential energy surfaces (PES) are essential for modeling chemical reactions at surfaces.
• Previous studies often used lower-dimensional models, potentially limiting quantitative accuracy.

Purpose of the Study:

• To construct a highly accurate nine-dimensional (9D) potential energy surface (PES) for the dissociative chemisorption of water (H2O) on a rigid Ni(100) surface.
• To investigate the importance of full-dimensional quantum dynamics in characterizing the reaction.
• To evaluate the validity of the site-averaging approximation for this gas-surface reaction.

Main Methods:

• Developed a 9D PES using neural network methods, trained on approximately 110,000 energies from density functional theory (DFT) calculations.
• Performed time-dependent wave packet calculations to assess PES accuracy and convergence.
• Conducted 9D and 7D quantum dynamics calculations to determine dissociation probabilities.

Main Results:

• The constructed 9D PES is accurate and smooth, with small fitting errors and good agreement with DFT data.
• Full-dimensional 9D quantum dynamics yield dissociation probabilities significantly different from 7D site-specific calculations.
• The site-averaging approximation, using 7D dynamics, accurately predicts the 9D dissociation probability for ground-state H2O.

Conclusions:

• Full-dimensional quantum dynamics are necessary for a quantitative understanding of H2O dissociation on Ni(100).
• The developed 9D PES provides a reliable description of the reaction dynamics.
• The site-averaging approximation offers a computationally efficient yet accurate method for predicting dissociation probabilities under specific conditions.