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Chapters 1 -4 Presentation Slides for Science at the Nanoscale: An Introductory Textbook by Chin Wee Shong, Sow Chorng Haur & Andrew T. S. Wee National University of Singapore ISBN: 9789814241038 Hardcover August 2009 228 pages More information at www. panstanford. com/nanotextbook www. panstanford. com
Chapter 1 www. panstanford. com
Just how small is nano? Name Abbrev. size scale Sci. Unit Representative objects with this metre m 100 Height of a 7 -year-old child. deci- dm 10− 1 Size of our palm. centi- cm 10− 2 Length of a bee. milli- mm 10− 3 Thickness of ordinary paperclip. micro- μm 10− 6 Size of typical dust particles. nano- nm 10− 9 The diametre of a C 60 molecule is about 1 nm. pico- pm 10− 12 Radius of a Hydrogen Atom is about 23 pm. femto- fm 10− 15 Size of a typical nucleus of an atom is 10 fm. atto- am 10− 18 Estimated size of an electron. www. panstanford. com
Scale of Things Zn. O Nanorod (HRTEM image) Spacing between Atomic Planes ~ 0. 6 nm Ag 2 S Nanocubes ~ 40 --50 nm 10 -9 m 10 -10 m STM Image of C 60 Molecular Chain Stingray Red Blood Cell~ 11. 6 mm 10 -7 m 10 -8 m Nanocrystal: Diameter ~ 16 nm Housefly: Length ~ 8. 5 mm 10 -5 m 10 -6 m Microspheres: Diameter ~ 1. 2 mm 10 -3 m 10 -4 m Zn. O Nanorods Diameter ~ 100 nm 10 -2 m 1 m Human Hair: Diameter ~ 90 mm Abalone Shell (Length) ~ 2 x 10 -1 m Ant’s Compound Eyes ~180 mm STM image of Si(111)-(7 x 7) 10 -1 m Cu. S Dendrites ~ 4 mm www. panstanford. com
Scaling Down to Nanometer www. panstanford. com
Chapter 2 www. panstanford. com
Cantilevers Cavenagh bridge, Singapore’s oldest suspension (cantilever) bridge SEM image of an AFM cantilever www. panstanford. com
Molecular Vibrations FT-IR spectrum of ethanol molecules in liquid state (Wavenumber cm− 1 = Hz/c) www. panstanford. com
Brownian Motion www. panstanford. com
Nanobot – Artist’s Impression Artist’s impression of a nanobot killing a virus www. panstanford. com
Chapter 3 www. panstanford. com
Blackbody Radiation www. panstanford. com
One-Dimensional Potential Box www. panstanford. com
Wavefunctions Plots of the wavefunctions y(x) corresponding to different quantum states and the square of the wavefunction |y(x)|2 www. panstanford. com
Three-Dimensional Potential Box www. panstanford. com
Energy Levels in Potential Box Potential box with large dimension Potential box with small dimension www. panstanford. com
Energy versus kz for quantum wire www. panstanford. com
Potential Step www. panstanford. com
Potential Barrier www. panstanford. com
Energy levels of H, He+ and Li 2+ www. panstanford. com
Hydrogen Spectrum www. panstanford. com
Spherical Coordinates www. panstanford. com
Shapes of Angular Wavefunctions www. panstanford. com
The Stern Gerlach Experiment www. panstanford. com
Chapter 4 www. panstanford. com
Periodic Table of Elements www. panstanford. com
Unit cell for a variety of ionic salts www. panstanford. com
Crystal planes Miller indices - (hkl) notations are used to denote planes that intercept at positions a/h, a/k, and a/l (or some multiples of these) of the x-, y- and z-axes respectively (100) planes (110) planes www. panstanford. com
X-Ray Diffraction For constructive interference, path length difference = n n = 1, 2, 3 … www. panstanford. com
XRD Analysis Cd. S nanocrystals 2 nm Debye-Scherrer equation relates peak width W to the crystallite size D: 3 nm (111) (220) 4 nm (311) www. panstanford. com
Wave function for the interacting orbitals www. panstanford. com
Effective overlap between AOs www. panstanford. com
σ*(2 p) π*(2 p) 2 p 2 p σ(2 p) π(2 p) MO energy level diagram for N 2 molecule σ*(2 s) 2 s 2 s σ(2 s) σ*(1 s) 1 s 1 s N atom σ(1 s) N 2 N≡N molecule The electronic configuration of N 2 is: ( 1 s)2( *1 s)2( 2 s)2 ( *2 s)2( 2 p)4( 2 p)2
Formation of sp 3 hybridized orbitals www. panstanford. com
Van der Waals Minimum www. panstanford. com
Hydrogen Bonding H–F····H–F Simple hydrogen bonding between two diatomic molecules Hydrogen bonding between two carboxylic molecules Hydrogen bonding between carbonyl and amide group Intramolecular hydrogen bonding within one carboxylic molecule www. panstanford. com
H-bonding in Proteins Beta-pleated sheets Alpha-helices www. panstanford. com
H-bonding in Deoxyribonucleic acid, DNA www. panstanford. com
Assemblies of Supramolecules An assembly of a rotaxane An assembly of a catenane C. A. Stanier, M. J. O Connell, H. L. Anderson, W. Clegg, J. Chem. Soc. Chem. Comm. , 2001, 493. M. Cesario, C. O. Dietrich-Buchecker, J. Guilhem, C. Pascard, J. P. Sauvage, J. Chem. Soc. Chem. Comm. 1985, 244. www. panstanford. com