Nanochemistry Course Goals and Outcomes

1
NanochemistryCourse Goals and Outcomes

• By the end of this course students will
• understand periodic trends and their relation to
  the properties of nanomaterials,
• be able to explain bonding in nanomaterials,
• describe the role of quantum mechanics in
  nanotechnology,
• interpret basic spectroscopies for ID and
  analysis of nanomaterials,
• be able to find, read, and interpret current
  literature relating to nanomaterials.

2
Bonding and Periodicity
3
size
EN
4
Lewis Structures
H
H
HH







O
O











OO


5
Molecular shape
Graphics from Atkins and Jones, Chemical
Principles, 4th ed.
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ED Theory ED Theory d- and f-block d- and f-block
Domains Shape Coordination Number Shape
2 Linear 2 Linear
3 Trigonal planar Bent
Bent 3 Trigonal planar
4 Tetrahedral 4 Tetrahedral
Trigonal pyramidal Square planar
Bent 5 Trigonal bipyramid
5 Trigonal bipyramidal Square pyramid
See-saw 6 Octahedral
t-shaped Trigonal prism
Linear Trigonmal antiprism
6 Octahedral 7 Pentagonal bipyramid
Square pyramidal Capped octahedron
Square planar Capped trigonal prism
9 Tricapped trigonalprism

7
Molecular Orbital Theory
Graphics from Atkins and Jones, Chemical
Principles, 4th ed.
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Molecular Orbital Theory
H2 s
H 1s
H 1s
H2 s
9
Complex molecules
10
Fundamental Chemical Understanding
The Molecular Structure View
3. What is the energy profile of the process?
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Fundamental Chemical Understanding
The Electronic Structure View
The Molecular Structure View
1. Where do atoms begin and where do they end?
Where do electrons begin and where do they
end?
2. What is the mechanism of the process?
3. What is the energy profile of the process?
Energy
Reaction coordinate
12
Orbital Energy Levels
Vacuum level
Molecular orbitalenergy levels
13
Orbital Energy Levels
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A Technique for Measuring Weak Magnetic Fields

• SQUID

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Band Theory
16
Lattice Vibrations
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Main Group Nanomaterials
Shallcross, R. C., et al J. Am. Chem. Soc. 2007,
129, 11310-11311.
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Carbon Nanomaterials

• Bucky Ball1985
• Nanotubes1991 (in dispute)

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References regarding carbon nanomaterials

• From recent issues of ACS Journals

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Quantum Mechanics

• Atomic and molecular structures are governed by
  the laws of quantum Mechanics. Understanding the
  quantization of electron orbits and molecular
  orbits can only be achieved in the framework of
  quantum laws.

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Quantum Mechanics
22
Blackbody Radiation
23
Einstein Photoelectric Effect
e-
e-
e-
e-
hv
Ehv - Ee- Ionization Energy
24
Atomic Line Spectra
Continuous
Emission
Absorption
frequency
25
de Broglie Wave Equation
? h/p
? h/p hc/E for light
? h/mv for particle
h Plancks constant
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Heisenberg Uncertainty Principle
A
a
w
a
E
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Schrödinger

• H? E?

H
Hamiltonian operator
E
Eigenvalue equating to energy
?
Wavefunction which must be an eignefunction
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Particle in a well
V 0
V 8
V 8
0
l
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Vibrational Motion
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Rotational Motion
Rigid Rotor
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Hydrogen-like orbitals
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Transition Metal Nanomaterials
Gibson, J. D., et al J. Am. Chem. Soc. 2007 129
11653-11661.
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Ln Nanomaterials
Boyle, T. J et al Inorg. Chem. 2007 46, 3705-3713.
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Suggested Experiments

• Field Emission Scanning Electron Microscopy
• Image nanoscale structures in this state of the
  art research tool.
• EDAX Energy Dispersive X-ray Analysis
• Apply x-ray or electron beam source in solids or
  liquids to determine elemental composition. Some
  outcomes Compare electron and x-ray penetration
  depths explore limitations when searching for
  low z elements direct exploration of binding
  energies for electrons in specific elements.
• Magnetization Small Ferromagnetic Particles
• Explore magnetic properties as a function of the
  particle size, proceeding to the single domain
  and superparamagnetic limit. For large particles,
  a ferromagnet shows irreversible magnetization
  behaviour in an applied field due to domain wall
  pinning, resulting in hysteresis and AC losses.
  In a superparamagnet, with a single preferred
  direction of magnetization, the direction of the
  magnetic moment can be destabilized and
  fluctuates as the temperature is raised. The
  relevant energies are kT, the thermal energy, and
  the anisotropy in the volume of the particle. At
  low temperatures, one sees to so-called blocking
  temperature above which the magnetization
  fluctuates and below which it begins to become
  more static. Illustrate time scales of the
  phenomena and the relationship to the time scale
  of the measurement.
• Quantum Dots Optical Properties
• Measure optical fluorescence of quantum dots with
  various dimensions
• Resource Fotios Papadimitrakopoulos
• Quantum Conductance
• Monitor conductance of nanoscale conductors as a
  function of temperature
• Resource Mark Reed
• Scanning Tunneling Microscopy
• Based on electron tunneling, which exponentially
  decays as a strong function of distance from a
  surface. Measure I(s) curves to demonstrate
  exponential current decay as predicted. Measure
  I(V) to measure conductors and insulators to
  observe band gap effects.
• Atomic Force Microscopy
• Use this state of the art instrument to measure
  nanoscale structures including nanotubes and IC
  components. Determine topography of structures,
  measure forces during indentation and attractions
  during retraction, measure mechanical variations
  through AC imaging methods, and possibly even
  manipulate a surface (eg nanotubes) by pushing
  structures with the tip itself.
• Nanoparticle Solar Power Generation
• Fabricate and test a nanoparticle-based
  dye-sensitized solar cell (Graetzel cell)
• Construct several solar cells by depositing TiO2
  particles of various sizes (including nanoscale
  and micrometer sized) onto conducting ITO coated
  glass. Sinter at low temperature (500C). Add a
  light absorbing die (soak in dark berry
  juiceperhaps test different berries), seal with
  a a top electrode coated with a catalyst
  (graphite from a pencil), and test as a function
  of illumination intensity and/or wavelength. Kits
  are directions are available for this very simple
  and cheap experiment online at