Introduction to Surface Science CM4020 Part 1

Course Information

• Course code: CM4020/CM6014
• Course title: Introduction to Surface Science and Surface Analysis
• Lecturer: Dr Brenda Long
• Email: [email protected]

Part 1: Surfaces, Adsorption & Catalysis

• Surfaces:
  • Single crystals have cubic unit cells.
  • Miller indices describe surface structure and methodology.
  • Unit cells have specific volumes.
  • Surface atom density is a key property.
• Adsorption Process:
  • Kinetics of adsorption are important.
  • Adsorption isotherms describe equilibrium.
  • Thermodynamics govern adsorption processes.
• Surface Reactions and Catalysis:
  • Adsorption of single reactants is the first step.
  • Reaction mechanisms are crucial in catalysis.

Part 2: Analytical Methods

• Ultra-high vacuum systems: Essential for surface analysis.
• Temperature Programmed Desorption: Used to study reaction order.
• Electron Spectroscopy:
  • X-ray Photoelectron Spectroscopy (XPS)
  • Auger Photoelectron Spectroscopy (APS)
  • Ultraviolet Photoelectron Spectroscopy (UPS)

Trigonometry Revision

• Right-angled triangles:
  • Area = 1/2 * base * height
• Equilateral triangles:
  • Area = √3/4 * side²
• Numerical examples using given dimensions for right-angled and isosceles triangles to determine area are presented

What is a Surface?

• This section discusses the physical and chemical properties of surfaces.
• The physical features include edges, defects, holes and layers.
• Atoms, chemical groups and dangling bonds are examples of chemical properties.

Solid Materials

• Amorphous materials: Lack ordered atomic arrangements.
• Single crystals: Exhibit repeating atomic structures.
• Polycrystalline solids: Made of many individual grains with different orientations.

Single Crystal Surfaces

• Crystal structure is defined by the unit cell, the simplest repeating unit.
• Unit cells contain lattice points defining atomic/ionic positions.
• The entire structure forms from repeating unit cells.

7 Basic Crystal Structures

• Basic shapes (e.g., cubic, tetragonal, hexagonal, orthorhombic, rhombohedral, monoclinic and triclinic) in crystal structures are categorized by edge lengths and angle measurement.

Lattice Point Locations and Cubic Unit Cells (Simple, Body-centered, Face-centered)

•  Different arrangements of atoms in cubic unit cells (Simple Cubic, Body-centered cubic, Face-centered cubic) are visualized

Calculating Unit Cell Volumes

• Unit cell volume is calculated based on density, molar mass, and cubic structure.
• Determining sides/radii of atoms in the unit cell are possible after calculating volumes.

Simple Cubic

•  Atoms at corners of a cubic structure.
•  Distance between atoms corresponds to twice the atomic radius.
•  Numerical examples (calculations using known density, mass and cubic unit cell characteristics) are provided

Body-Centered Cubic

•  Atoms at corners and center of cubic unit cell
•  Numerical examples are included.
•  Packing efficiency calculation is explained

Face-Centered Cubic

•  Atoms at corners and center of faces of cubic unit cell.
•  Numerical examples are presented

Density of Surface Atoms

•  Calculations of density of atoms on crystal faces are described

Calculation (Copper example)

•  Calculations of number of atoms on the 100 surface of copper are displayed using dimensions and structural properties of copper.