CO Inversion on a NaCl(100) Surface: A Multireference Quantum Embedding Study.

Area of Science:

• Surface science
• Quantum chemistry
• Computational materials science

Background:

• Vibrationally excited carbon monoxide (CO) molecules exhibit isomerization on NaCl(100) surfaces.
• Understanding the mechanism of CO isomerization is crucial for surface chemistry and materials science.

Purpose of the Study:

• To investigate the isomerization mechanism of vibrationally excited CO on NaCl(100) using a multireference quantum embedding model.
• To develop and apply a reduced potential energy surface for CO/NaCl(100) interactions.

Main Methods:

• Utilized second-order multireference perturbation theory and active space embedding theory (ASET).
• Modeled interactions for isolated CO and CO monolayer (1/1) on NaCl(100).
• Generated potential energy surfaces and performed vibrational analysis.

Main Results:

• For near-equilibrium bonds, C-down CO is more stable than O-down.
• CO bond stretching reverses the energetic preference, supporting the isomerization mechanism.
• Vibrational analysis shows small shifts consistent with experimental data; CO-CO interactions stabilize O-down in monolayers.

Conclusions:

• The study validates the accepted CO isomerization mechanism on NaCl(100).
• Quantum embedding models provide accurate insights into surface adsorbate dynamics.
• Intermolecular CO-CO interactions significantly influence isomerization pathways in monolayers.