Ring Polymer Molecular Dynamics Rates for Hydrogen Recombinative Desorption on Pt(111)

Area of Science:

• Surface Science
• Chemical Physics
• Computational Chemistry

Background:

• Recombinative desorption (RD) of hydrogen on Pt(111) is vital for heterogeneous catalysis.
• Accurate experimental data for H2 RD rates provide benchmarks for theoretical models.
• Understanding nuclear quantum effects is crucial for precise reaction rate predictions.

Purpose of the Study:

• To apply ring polymer molecular dynamics (RPMD) rate theory to H2 RD on Pt(111).
• To investigate the role of nuclear quantum effects, including zero-point energy and tunneling.
• To compare theoretical predictions with recent high-accuracy experimental measurements.

Main Methods:

• Utilized first-principles potential energy surface calibrated with experimental data.
• Employed ring polymer molecular dynamics (RPMD) rate theory.
• Calculated H2 RD rate coefficients across various temperatures.

Main Results:

• RPMD rate coefficients closely matched experimental data (within a factor of 2).
• Demonstrated the capability of RPMD theory in handling quantum effects in surface reactions.
• Identified reactant zero-point energy as the dominant nuclear quantum effect.

Conclusions:

• RPMD theory is a reliable method for studying surface reactions with quantum effects.
• Zero-point energy plays a more significant role than tunneling in this H2 RD system.
• The findings offer valuable insights into the mechanism of heterogeneous catalysis.