Configuration interaction approaches for solving quantum impurity models.

Area of Science:

• Computational chemistry
• Surface science
• Quantum mechanics

Background:

• Understanding molecule-metal surface interactions is crucial in catalysis and materials science.
• Accurately describing electron correlation in adsorbates on metal surfaces presents significant theoretical challenges.

Purpose of the Study:

• To develop and apply configuration interaction methods for characterizing the electronic structure of adsorbates on metal surfaces.
• To provide a robust description of adsorbate on-site electron-electron correlation.
• To lay the groundwork for extending these methods to more complex ab initio Hamiltonians.

Main Methods:

• Configuration interaction (CI) approaches are employed.
• The Anderson impurity model is used as a restricted test case.
• Methods are designed to handle the presence of a continuum of electronic states.

Main Results:

• The developed CI methods provide a reasonable description of adsorbate electron-electron correlation.
• The study demonstrates the feasibility of characterizing electronic structure for model adsorbate-metal systems.
• The approach is effective when the adsorbate can be separated from the substrate.

Conclusions:

• The configuration interaction methods show promise for electronic structure characterization of adsorbates on metal surfaces.
• These methods can potentially be extended to ab initio Hamiltonians for more realistic systems.
• The work offers insights into the structure and dynamics of molecule-metal surface interactions.