Modelling an MgO surface

A case study by Joe Jackson-Masters and Rowan Hanson, Cardiff University. Funding is gratefully acknowledged from CCP5.

Contents:

• Setting up the QM/MM Cluster
  • Preparation of a surface cluster
  • Partitioning the cluster
• Single-Point Energy Calculation
  • 1. Quantum Mechanics (QM)
  • 2. Molecular Mechanics (MM)
  • 3. Calculating the Single-Point Energy
• Geometry Optimisation
• Adding an Adsorbate
  • 1. Optimised Energy of Adsorbate
  • 2. Optimised Energy of the Adsorbed State
• Vibrational Frequency
• Ionisation Potential
• Appendix: Generating a Force Field

The following tutorial focuses on an ionic MgO surface in a QM/MM environment. This tutorial will illustrate a method for performing energy calculations on a solid surface involving cutting and partitioning a cluster. Later, the tutorial will also demonstrate how an adsorbate can be included, in order to study surface reactivity.

It is recommended that crystal structures are obtained from ICSD. The citation for the MgO crystal structure used in this tutorial is: American Mineralogist (1976) 61, (*) p266-p271.